Trimble S5 locking onto road signs while using active prism?
I'm a fairly new user to an S5, about 1 year, and if I'm shooting the active prism I've never had it lock on anything else. If set to passive, yes it will lock on all sorts of reflective items. Its pretty neat to see it lock on the license plate of a car and follow it a few hundred feet down the road.
In the passive prism mode my S6 will lock onto just about anything reflective, including falling snowflakes!