I do not know what their criteria is, however I would think they would want want play-testers who are already customers and have their own debit/credit cards. They would need a way to charge for the demo if it is not returned. Basically, by asking to be play-testers we have agreed to being charged for the demo if not returned (being charged for not returning is in the first post.) As well they would want posters who have shown a certain amount of board presence (whatever that may be).
If I was them I would not send racquets to users who fail to meet at lest those points mentioned..