It will never be acceptable for a new player to be "squelched" for only making the mistake of choosing a game ID of someone who was a problem. There is no time period which would make it acceptable.
Suggestion:
Perhaps it could be a drop down list that you type <player id> in the roster that activates a batch .squelch command. You type players on the list, and each time you log in you have to activate the list (push activate button) and the list entered, batch style in the radio buffer. If an ID is no longer active, you get an error, due to <player> id being invalid. This keeps the list from going active until you delete the inactive ID. In this way, once "Vinkman" quits, in a very short time, those that had him on their squelch list would have to clean him off the list, making it ok for a later player who picks "Vinkman"
Not a perma squelch, but a list that needs to be activated each time
List is easy to activate.
List is easy to update/modify
List only activates if all IDs are valid.
If players want to pay for several shades, it's eazy to keep up
If players change their ID to avoid squelching, the 'Error' message lets me know the old name is no longer in service.
Since you see the list every time you activate it, no chance of forgetting who is on it.
Reasoning: 200 will be more civil if folks know it's easy to end up on a squelch list.