Try City Living Free For The Weekend

This is really nice for people that want to try this stuff out, but I'm wondering if the free trial is forced on all accounts? Or can we say no to it when prompted? I already have City Living so I don't know if I can even test that.

I just really hope this is optional, because I don't want DLC that I don't plan to keep infecting my legacy save. If I can't say no, then any time there's a free trial weekend for a pack I don't have, I'm locked out of playing Sims 4, because I don't play any other save files.