I've just seen the mumsnet advert for playdate cards here
'Tired of reminding other mums that your child can't swim or loves to play football?' (I'm not going to mention the allergies thing, because I can see the use in that).
Well if I invited a child round and I got a card telling me that he didn't eat peas, only likes to play lego and hungry hippos and will definately not like to do puzzles then I think and I think I might cancel, not because of the child but who wants to get involved with parents like that?