Except in cases of blatant spam, porn, etc. we don't ban members without explicit warnings first. Our staff works hard NOT to ban members, and we do all we can to work with members to help them keep the rules so they can stick around.
Unfortunately there are rare cases where members can't stop themselves from breaking the rules, even after being warned, and we are forced to block their access to the forum.
Some bans are temporary and some permanent. Each and every case is unique and the severity of the situations and tone of the member vary wildly. For example, some people just aren't good at controlling the way they come across while other are intentionally flaming, trolling, or stirring the pot.
We have an amazing group of staff members that love this community. We're lucky to have them and their diverse experience and points-of-view. This makes the discussion process on each situation that more interesting and important. Of course, each case is discussed between the staff before action is taken.
NOTE: Sometimes it may look like we banned a member without any warnings, or for "no reason", but please remember that unless you are a forum moderator, you do not have visibility into all the behind-the-scenes problem reports, private messages, discussions, etc. we see. Again, we do all we can to keep all our members here, but there are times when we have to weigh the overall benefit of someone being here vs. the problems / drama they are stirring up for the rest of the community and the staff.
This is a good thread with more info:
https://www.backyardchickens.com/forum/viewtopic.php?id=182235