Disney is very particular (and rightfully so) about people following the rules when it comes to FastPass+ reservations and tickets. So, we totally understand when people want to be cautious about being sure that they abide by all the policies that Disney has in place. But what about when you have a traveling companion that decides they don't want to ride something? Can somebody else use their FastPass+ reservation?
Disney makes it seem like you'll be able to handle everything with just your MagicBand. Want to buy something? SCAN YOUR MAGICBAND! Need into your room? SCAN YOUR MAGICBAND! Want Mary Poppins to clean your house? SCAN YOUR MAGICBAND! (I made that last one up.) And, while that is true for most things, it isn't for everything.
As a frequent offsite trip taker with my family (GASP! I know! The horror. But listen: I have 2 grown kids. We can either stay for 10 days offsite in a nice big rental house where everybody has their own room OR stay like 73 hours in a suite onsite) we are quite familiar with using MagicBands on offsite trips.