OK - so here's why I think it would be a good idea:
! - you really need to talk to someone (ie: crisis)
! - you're having trouble with a recipe and suddenly a Cooking Angel comes online = you can get quick help, instead of having to wait for someone to notice your posting.
Personally, I think are equally important reasons to say Yes & to say No regarding private messages. But it would be nice to choose if a particular situation came up. What does everyone think?