This new rule is annoying me too - I had it a couple of times at London Bridge platforms 1-6 and they now seem to have rolled it out to the higher number platforms. There are some FAQs here:
http://www.southernrailway.com/your-jou ... -questions - but I note they have omitted the most important question which is "Why?"
I think it's a pretty dumb rule for any number of reasons - as someone else said, 11kg of metal folded into a compact parcel and being carried feels like it will do a lot more damage than a very visible bike being wheeled. Doubtless it will be "careless bicycle owners" if someone does get injured that way.
I wouldn't have such a problem with it if it was communicated more pleasantly - at the moment you get some jobsworth barking an order at you at the end of a long-tiring day and the instinctive reaction is to challenge it, particularly as there is no evidence at the station of the new rules (despite Southern claiming it has been clearly announced). On Wednesday last week, one of the ticket gate guards told me brusqely to fold my bike, and then told me mid fold to move it as I was now causing an obstruction. A woman with a Brompton next to me was complaining about this at which point some man dressed in black and with a walkie-talkie came over and joined in the "debate". When I suggested that wheeling bikes was surely no more dangerous than wheeling other items (e.g. suitcases) he started accusing me of saying wheelchair users should be made to fold their chairs and walk!
Here's a response I got from SouthEastern earlier this year when I complained about a ticket gate guard being rude and insulting to me when I asked why I had to fold my bike. Note it avoids commenting on the guard's rudeness.
"I can confirm that this policy has been in place for some time, but it has been necessary to enforce this policy more rigidly recently due to accidents and injuries inflicted upon other passengers by careless bicycle owners. It should be noted that some train operators do not allow folding bicycles to be taken onto a train unless they are kept in a case for this reason. Whilst we have not taken this step, and whilst we do still permit folding bicycles on our trains, because bicycles have peddles and handlebars jutting out, when they fall over on a busy train or platform, they can easily bruise shins or cause other injuries. Due to the potential risks we are asking passengers with folding bicycles to fold their bicycle before attempting to enter a platform, in the interest of safety.
Whilst I can appreciate that this policy is inconvenient for many cyclists, we believe that it is in the interest of the majority of our passengers. We are not obliged to offer the facility to carry any bicycles free of charge, and should the issue of unfolding bicycles become a problem at our stations or on trains in the future, it may become necessary to charge passengers for the carriage of any bicycle, or refuse the carriage of these during peak times at all. However, currently the number of non-folding bicycles carried on trains at peak times is relatively low, and we hope that by working together with cyclists to reduce the hazards and inconvenience associated with carrying bicycles on trains, such action will not be necessary."
I didn't have the will to challenge the claim about accidents and injuries inflicted by careless bicycle owners, although I now wish I had. Given I live on the Brighton line, it's not folding bikes that cause inconvenience but the enormous suitcases people take to and from Gatwick!
Anyway, rant over - feels good to know I'm not the only one irritated by this. But I suspect we will have to put up with it.