Selling etiquette

I should have asked sooner, but I've been a member for about 10 years. Never really sold much. I don't even have a score. So, if someone has a low trading score( in the 70's) ,and most of their posts seem to be buying, and selling, and they ask about a postal MO, should I be concerned?
Also, is PayPal friends and family ok to accept from a buyer with a 100% score who's been around a while?
Not trying to hurt anyone's feelings, but I do want to protect myself.