- When you restart your masternode with either "masternode start" or "masternode start-many" or "masternode start-alias" command, you are forced to the back of the queue.
Please remind, what for?
Let me correct this ^^^^^

Daemon restart is ok.
Ok, I meant it. The question is still actual. Is there any kind of exploit that fixed with that measure?
If a restart put you in front or even the middle of the line, then someone could just restart constantly to get extra payments.
This is only for protocol changes, so updating daemon from .50 to .51 doesn't require a restart from the cold wallet and you don't lose your place.
