I occasionally lose some points because a user gets removed from Stack Overflow (and other sites). How does this happen? Should I be worried about being booted from Stack Exchange because I don't always know the rules?
It takes quite a bit to have a user removed, and it's usually things that are really dumb, like serial voting (for badges or revenge), sockpuppets or extreme examples of trolling. Spam bots get nuked too, but that's generally a net gain.
If you're going to get your account deleted, and you're a real user, chances are you'd get at least a warning of some sort, or are engaged in some sort of activity that common sense and the rules suggests you don't.
In no way are account destruction or deletion arbitrary, and you're probably not next.
Alternately, some users choose to delete their accounts, for various reasons. In this case, it takes an active request and may be reviewed for a high reputation user. In this case though, the user will certainly know about it.
There are a few ways to get your account removed without explicitly asking for it. It's pretty obvious they would be things that would get you in trouble.
creating multiple accounts (sock puppets) and using those accounts to do things you can't do with one account e.g. vote on your own posts or vote multiple times on the same post
Most other disruptive actions are handled by moderator warnings and suspensions rather than removal of accounts.
A few other reasons for account deletion:
- Creating another account to circumvent suspension or post ban / rate limit (even if it does not interact with the suspended / rate-limited account)
- Using the Stack Exchange network while being under 13 years old is a violation of the terms of service and will result in account deletion.
- Accounts are deleted in the process of merging which may be requested by the user, or triggered otherwise and possibly reviewed by Stack Exchange staff. The merge may result in some votes being cancelled, for example if two accounts voted on the same post.