I think that would be a good idea, Mary, but there are some people that are newbies that change into regular posters (myself included) - and sometimes, to gain credibility, a newbie may be posting an offer (under the theory is people don't know them yet, so maybe they give away some things to gain credibility -or- the don't post regularly but they've been an FT'er for several months or years and now they have something that they could use or would be interested in listing on the coupon connection. Alternatively, you could put a note in the bottom of your post stating that you do not wish to trade with non-established FT'ers or non-registered users. That's well within your rights.
I have traded with several people that are new and have had wonderful experiences. In fact the most generous FT'er I've traded with only had 23 posts and he sent me his item and trusts me to send him mine (which I will, of course).
Certainly, there are people that may abuse the Coupon Connection and "prey" on newbies who don't know any better and solicit trades, but in reality, if you are posting on a public forum (which I realize Randy owns, but essentially, it is a public forum - we have about 25,000 registered users!) then you are opening yourself up to people e-mailing you about them - to avoid this, I would recommend removing the public viewing of your private e-mail address from your profile or creating a flyertalk specific e-mail address (which, to my knowledge, will still allow you to receive e-mail notifications for topics you start).
One of the people I just made an exchange with didn't post a YGM (because he may not have known to do so) - yet, it was a trade that worked out in both of our favors.
And as for the lurkers & trollers that reply when you are looking for or getting rid of something, ask them for their FT handle, if they don't respond, they don't have one, or if they send it to you, research it to make sure it matches to their listed e-mail addy on FT and check them out. Of course, there is always the possibility that the lurker or the troller does have what you need in which case, go ahead and trade if you are willing to.
You can always say that you don't want to trade with people below 200 posts if you'd like to filter them out. Or you can try trading amongst FT'ers that you have already traded with before putting it on the Coupon Connection.
The Coupon Connection already has some really great Moderators, Chuck always closes threads that shouldn't be open there. We have the FAQs and there's even the Voluntary Coupon Connection rules. Most people are good hearted on the CC. I've only done maybe three or four trades that the items in question were over a hundred bucks, but every single time, although I've been worried about being screwed over, it's always worked out.
I think that the trollers & predators that you are talking about are generally ignored by people on FT & if they aren't, it's probably because the other person is really interested in trading. There have been times that I wanted a lounge pass and a particular FT'er e-mailed me unsolicited - at first, I was about to flat out reject him and tell him not to e-mail me again, but after I heard what he had proposed, I felt that the trade was mutually beneficial and it worked out just fine.
So, basically, I think that could be a good idea, but if that were to happen, it would limit a lot of input and community that is Flyertalk.