I think it gets obvious the longer someone has owned a BP... If they're stiff, moving quickly, flinching, this is all stress or fear.

If they're slowly checking things out, looking around a bit, stopping to relax, and their bodies are squishy (lol), they are relaxed.

Yeah, moving around too much inside the enclosure means something is off. Either they pooped, they're hungry, the temps are wrong, or they don't have good hides/don't feel secure in there.