By far the most GUESTs here are very nice persons contributing valuable questions and responses. I'd miss them if they'd have to stay out and it would be a stupid action to ignore them as a rule.
However, if you read a particularly nasty post with a personal attack and you look who has authored it, the probability is high it was a GUEST. These are the posts to ignore.
As for the flaming GUESTs, if I think they are outside flamers stopping over for a few posts they consider 'funny', I shrug them off. The flaming GUESTs that bother me much more are the ones with inside knowledge who obviously are Mudcatters using the GUEST anonymity for personal attacks on people they know more or less well. A rather mild word describing what I feel for them is: contempt.

Wolfgang