The only problem I see with this is it will encourage a more closed off community. It would create a situation where in order to avoid the spam, players remove themselves.
You would miss out on legit random tells like, "Nice shield. Where did you get that?" "Hey Killsalotofyou, how are things going? This is Morfgarg. I'm at a friends right now (different character)." "Can you help me?" "Is your guild recruiting?" "Hey Morfgarg, I just created a new Monk character."
Once a channel or filter becomes the default spam filter, it will be turned on or will be out of the way"
There are a lot of other sugestions out there that would provide the desired result of eliminating spam, without forcing anti-social behavior as the fix.
Here is a solution I posted in the SPAMMERWRATH thread:
My solution - if a trial account gets more than 15 squelches from tells to paid accounts, the account can send messages but they don't go anywhere. The plat sellers could be sending tells to nobody, wasting their time. Sure, they could check on another account to see if their message is getting through, but it would slow down the process. Also, it would force them to create a new account to get maybe 30 more tells out.
There are a lot of other viable options out there. Most of the problems exist with trial accounts. Most don't want a solution that ignores legitimate new players or drives the community into isolation.