Any player may, on their turn, reduce another player's score by any number of points provided they also reduce their own score by this many points. Their score may not fall below 0 this way.
Unanimity (not majority) is required for rule changes on the first two turns:
203. A rule-change is adopted if and only if the vote is unanimous among the eligible voters. If this rule is not amended by the end of the second complete circuit of turns, it automatically changes to require only a simple majority.
According to the rules, everyone has to vote on every rule change.
I vote yes on Tom's proposal since there's no actual chance of it being passed and I can now constantly take the moral high ground if Tom votes against any of my proposals.