Ok so Jam function seems incredibly odd to begin with, but I suppose in a rare instance where you want to listen to love songs with someone who's far away at the exact same time, or you're running a silent Disco, there might be a use for it for a very small number of people.
But there should be an option to disable it in your settings. Let's start with the hypothetical scenario that I don't want to run into: A crazy ex or a stalker trying to send me their sad playlist everyday. Also, and possibly more frustrating, is the automatic prompt that comes of when you and another person listening to Spotify are on the same Wi-Fi. Why am I being sent an unprompted question without an invitation from another user in my home or business if I would like to join and listen to exactly what they're listening to at the same time. If I happen to want that, would I not just play the music aloud? We obviously already started listening to what we want to listen to on our own devices by ourselves, so why would I suddenly want to listen to exactly what they want to listen to? Automatically searching for users on the same Wi-Fi seems crazy intrusive to me what if we're on a public Wi-Fi at a mall? How many prompts would you'd be receiving to join? Anyway I don't mind if this crazy feature (that I'm willing to bet a Year's membership that under 5% of users use monthly) stays on the app, I just want the ability to turn it off so it doesn't bother me while I'm listening to music by myself.