Wrong. Reasonable suspicion isn't the argument -  as it's non-existent negated when 'consensual contact in a public place' is the setting. They aren't pulling people over to talk to them, they are making contact in a public place; hence, no reasonable expectation of privacy attaches. The contact is consensual SIMPLY because of the forum itself - not in the sense that consent is given and consent then facilitates the contact. This is like saying that a process server can't serve papers in a courthouse or library. The parties all have a 'right' to be on public property.