I know a couple of RAF sqns that have compulsory PT and while a lot of people bitch like mad, there is often no better motivation than to look a complete wheezemeister in front of your mates.
Like a lot of things (including the introduction of the RAFFT itself), group PT would take a culture change across the station in order to be accepted, but accepted it would be. If a percentage of the unit were to partake first thing in the morning, after a while the station would adapt. It's very easy to say "it won't work", but everyone would have to MAKE it work. The Army manages it (even those based on an RAF unit such as Odiham), so why couldn't we?