Don't allow to vcall unlimited timelimit
Xonotic has a long known bug of overwhelming lag when the match clock exceeds certain limit (like 2000 minutes). OTOH xonotic has a common "timelimit" vote (not default, but most admins add it), which allows a match to continue indefinitely. This sometimes leads to people confused about the lag, complaints to admins, etc.
I think given the existence of the bug we should never allow to set timelimit larger than maybe 500 minutes (perhaps have a separate cvar to control the upper limit?).
Related issue is unlimited warmup time which leads to the similar problem. Packer has a script to restart the game if warmup exceeds 1 hour, but it would be better if we supported this out of box. Also if implemented in QC it would be more readable and maintainable.