More heatsinks are an option, radiator fins are the only allowed , and passive means to get energy in the system to combat freezing.

And I do understand the possible mistake. I myself, even if I never used the heating methode, should have known better.
But Mentorn didnt allow bottleheaters.And the rest of the system had a handy arena heater with the flamepit.
This gave some of the seniors the wrong idea in the rules.

Fysicaly, there is no problem with heating the system. This should be protected by the 1000psi PRD.
Except the bottle, and even if the bottle is overheated the burst disk would prefent worse things.

As with all things concerning CO2, we full pressure users have to keep track of a few more,and much more restricting rules than any other robot builder. Spinners are the next runner uppers in this, and these machines are more restricted by the enviroment than by the rules themselfs.
Even if the old Mentorn Rules covered 99% of the potential problems with pneumatics.