Is putting your bike upside down wrong? 67% of you say not, so why the controversy?

Upside down on a grass verge - no scratches:  or at a pinch take off your gloves (because always wear gloves obvs) and place under the hoods to protect from the tarmac, and your waterproof under the saddle if you're that worried about it.  

(If the saddle gets ruined from standing upside down for a couple fo mins, what kind of surface are you standing it on - Sandpaper? Molten Lava?)

Laying it on it's (non drive) side makes it harder IMO to remove wheels etc and scratches the whole side of your 'bars / grips / tape and saddle.  At least standing upside down it doesn't slide about.

The "Safety Warning" from Shimano strikes me as the typical over eager safety guff all manufacturers put on all equipment (if you've ever read the safety warnings that come with most cycle helmets for example, it seems that most of them are not meant to be worn for racing or dangerous riding....basically when they are most needed!)

Who pulls the brakes when it's upside down anyway? You can't really adjust / fix brakes when the bike is upside down...they're the wrong way round, out of reach......?

"You’ll also have to pick up your water bottles as they’ll have dropped out of their cages and rolled down the hill. It the cages haven’t relinquished their grip on the bottles, they might not be leaking sticking energy drink all of your frame."

If those things happen, the bottle cages and bidons should be replaced. If a cage can't hold a bidon simply by being turned upside down, it will have probably bounced out long before that anyway. 
My bidons don't leak either. I  use the cleverly designed Camelback bidons who ironically considering their early marketing slogan 'Unbottle yourself'  now make the best  water bottles. 

As for those folk scared about marking your precious saddle or hoods, here's a simply tip.
After flipping bike over, very gently rest bike on ground and nothing will be marked. 

Still not getting why I have to flip my bike over at all.

"Not Pro"?? We could all be more "pro" by having a mechanic and a coach follow us in the car. No need to flip the bike when there's a boot full of tools, a bike stand and somewhere warm to sit while a professional bike mechanic puts your chain back on. Maybe even get a massage while you wait. Far more "pro". 

Perhaps the reason some pros have rules like this is to separate them from non-pros. No amount of pretense will change that. You can follow all the rules you like, there will always be some pros who don't want to be associated with amateurs, and will invent a way to cement the differences. 

Given that many people criticize cyclists for not following rules, it seems ridiculous that we apparently have a rule for bike repair etiquette! 

Flip the bike if it makes it easier. Do it carefully. Remove the bidon first. It is your bike, after all. You are free!!

Upside down EVERY time. So much easier to take wheels off and no danger of chipping and scratching your paintwork on your forks etc. Laying it on the side is a bit naff, but each to their own. I've not damaged my saddle and hood rubber doesn't mark that easy...and can be cheaply replaced if need be (I haven't needed to in 9 years)

Pros get their bikes free, they couldn't care less about damaging the paint...ignore them...

Has anyone changed their mind on this issue since this was first posted?

HERETICS!

Here's another reason:

I was cycling with a friend last summer when her Di2 on her fancy new bike stopped working. It was a hilly area so we nursed it to a bike shop who tried to figure out what had gone wrong.

Turns out she had washed it upside down and water had got into the seat post and nerfed the battery. She looked sheepish and got the train home, then spent £100+ on a new Di2 battery.

Always a subject that flushes the gringos out of the undergrowth

I did turn my bike upside down once. Apart from everything falling out of bags, saddle and hood scuffs, everything was back to front, couldn't work it out. 

The reason you must never turn your bike upside down is that dust, rust and gunk could fall down the seat tube and get into the bottom bracket bearing.

Oh no, wait a moment...

[Joking aside, the cure for that is to cut a collar out of an old margarine tub and slip it around the bearing inside the bottom bracket shell. And an empty yoghurt pot makes a good receptacle to stop you losing the cotter pins while you're doing it!]

I say fook looking like a pro.  I'm not a pro and don't have a team car loaded with mechanics and spares following my every move.  Nor do I receive a new frame every year.   It's a damned sight easier to remove a rear wheel to fix a flat when the bike's upside down.  Never scratched or dinged a frame that way, but I do know a guy who bent a derailleur hanger while trying to do things the 'pro' way.

Oh Sheeesh! The things we clutch our pearls about. As long as your aren't on it when it's upside down, it's all good. 
Like previosly mentioned, just don't set it on you computer or lights. But then, if your dumb enough to do that, lesson learned

I have a cargo bike so I just take my Feedback Sports Pro Elite with me.

At my BMX club we encourage riders to park their bikes upside down.

This question is a bit like asking a group of Norwegians do you store your firewood bark side up or down, it’s  a good way to start a less than civil war…

For me it’s a moot issue. Since I recently sold my vintage road bike, I’m left with none I’ll be thinking about turning upside down anyway. Of my remaining bikes, 3 have Nexus hubs, and two of them have roller brakes (the Catrike has one as a drag brake), the Gazelle has a dynamo front hub as well. If there’s a flat on the road you find it and patch it with the wheel in situ or walk home because it’s a pita taking a wheel off. The other is a Tern GSD and you can stand it vertically on its rear rack.

As 'Froze' sort of mentions, not turning bikes upside down started in the days when all brake cables came from the top of the levers, so resting the weight of your bike on the junction between solid  lever housing and flexible steel cable would be likely to crush or kink the cable.

I've never turned bikes upside down because I got into the habit for the above reason and never got out of it. It just feels so wrong, but really that's not rational is it? Unless you have a vintage bike with up-sprouting cables obviously.