Yes. Kids are opportunistic. Wait until she's a teenager.
Yes. It is somewhat common for a 5 year old to be attracted to fun things/people over loyalty. Character builds over a lifetime. You have plenty of time to maneuver her behavior in relationships. I'm still guiding my 17 year old regarding interpersonal relationships.
You may want to try to create other expectations so your daughter values you and others more.
I wouldn't say don't give her the choice, I'd say don't give her the expectation.
Do you always do what she asks? Does she always go where you go? Let's say you always take her to the movies/mall/fishing/swimming/etc. She may come to expect you and situations to be at her disposal.
This may be a somewhat unique situation, but if you think about it, it can be very relate-able......
My uncle owns an airplane. Every time he went flying he took his son with him. After a few years, the son (5 -8 years old) became quite bored with my uncle and the activity. He acted like a spoiled brat.
We made the same mistake with our daughter regarding travel. She became "bored" with travel around middle school age. We left her home a couple of times. That helped a lot.
I remember my uncle saying to me "Sometimes, as a parent, you have to say no to things. Even if you don't want to. People become bored with people or things when they get everything they want or if they can have things/people on demand."
Don't worry too much about it. You may want to take her for car rides (or long walks) and talk about friendship, loyalty, etc. Kids are very receptive to conversation on car rides. It's also a great time to build trust and add depth to your relationship.