Yeah, it’s obviously not for you @bubinga5 - if they’re trying to make a go of being (or are an existing) working band, the “hey lets jam” approach will be met with ‘but you learned the songs though?’
Having run 2 covers bands, and auditioned some members - i’d politely ask someone to leave the room if they wanted to jam (and hadn’t prepared).
Now, in an originals setting, I’d love the “hey lets jam” approach.