I do photobooths. Just did one this last weekend. I don't love them, but for an extra grand, I have no problem setting one up. I just am not keen on cleaning the alcohol stained props afterwards. Its a trend, and it will probably pass. But in the meantime, it doesn't hurt to increase revenue by offering it. I already have all the equipment necessary, just needed a $50 trip to the dollar store to buy all the props.
Honestly, for an extra grand, wouldn't you set one up on a wedding day you're already working? Its a no brainer to me.