The sites I’ve been too that only allowed Bio , 1st just said you had to use bio, no checking just relied on the players honesty(trusting fools !) 2nd said you had to show an unopened bags/bottles with the seal intact and the 3rd you had to buy their ammo no other could be used no matter wether it’s a new a sealed bag or bottle and if you where caught using anything else you'd be kicked off site and banned immediately !
Personally, I have no problems using PLA-based up to 0.32g, since we're not talking much of a difference in price (although we're not talking about much of a difference is biodegradability in UK woodland either).
Above that, the amount of "plastic" in the BBs starts to tail off, the price rises sharply, and there are few of them being left on the ground to begin with, so it gets harder to justify being the goodest of boys.
I think ACE will be pretty loose with the BIO's for a while Les..will take some time for it to sink in with peeps about using bio's... I myself have around 30k normal sat around, which I will slowly get through. I've also bought a couple bottles of Bio 0.28's for the Rozzer's to check.. **Sorry I missed you on Sunday mate btw, was quite i'll...and I've broke my little toe as well later in the day being a clumsy tool. Ugh....The day was also booke off as Holiday. lololol