The real question is why did Mom not make any attempt to ceasefire Sanc, when they knew an incoming notice from Havoc was on the table? Here I was sitting all postwar waiting for such a request, and when it didn't come I assumed mom intended to dodge havoc by waving us. But now the only thing I can come up with is that mom intended to stand by the ludicrous/debunked "havoc can't notice us until we ceasefire Sanc" argument.
And no, feeling entitled to acres does not entail 'well, we tried'.
If you're going to quote history, you should make an attempt to get it right. In that 5-year-ago war Havoc had already noticed Mom prior to them starting a fight against Sanc. They fought Sanc to dodge Havoc, then attempted to rewave Sanc to dodge Havoc again. At the end of the war they were vultured by Havoc and Sanc was vultured by PewPew. At no point did Havoc give notice into a hostile or dealbreak Mom. I would not put that incident up as an example of fair play, but it also did not involve dealbreaking.