What do you need to effectuate a seizure? Reasonable suspicion.
Just approaching and asking questions isn't a seizure,
of course. What does it mean to consent to a seizure?
You're seized when a reasonable person (not the specific
person in the incident) would feel like they couldn't leave.
The difference between Royer and Mendenhall
is that Royer's ticket was taken.
Oh, and who is a "reasonable person?" In reality, this
probably means the judge.