TLDR - Who runs "the feds" can change. New admins aren't obligated to keep the promises of the old admins, particularly when those promises include things like "we promise not to enforce law X or law Y".

Indeed. If you could rule by promise, and those promises were binding on future administrations, then executive power would be practically unlimited.

I can't say I blame her for deciding either way (apart from coming here without authorization.) It was a calculated gamble -- essentially 5 years of guaranteed immunity in exchange for being easier to find if the feds had decided to show her the door.

Had she stayed in the shadows, she might have been caught and deported regardless. I don't have the data to accurately weigh her chances either way.

In any event, her most likely outcome right now is deportation, then sneaking back in.