Sure, just casually steal from her maids and come back for more. On one hand, she could get even with him. On the other, this seems like the perfect opportunity to start an enterprise (Read: Plagiarize all the Earth goodies) and get some fame and funds that her corrupt uncle can't embezzle.
What would I do in an isekai, huh?
I think I'd have to tackle it very methodically. First of all, what kind of world is it? Is it a world that loves me like Smartphone(the bad one), or one that hates me, like Konosuba? And am I the protagonist of said world with cheat skills, or just my lame self?
If things are favorable, heck yeah I'll enjoy myself. Generally lay low, but be ready to bite back the moment anyone starts beef. If not, survival is the name of the game.