Sounds like bs to me tbh, you can use emotes that "stall" your character such as a skill cape emotes and turn on all the prayers, but once its over most of them turn off and it only leaves the ones that are supposed to be on. You cannot interact with anything during an emote like that so its pointless and also client side now that I think of it as the prayers don't actually turn on. He's had over a week to give us some sort of proof which we have yet to see.
Edit: Well I guess we won't see that proof and assume it was bs as he's banned now.