Most of these apps either cycle the wifi periodically to check for known hotspots, or they use the cell towers to determine location. I guess this program uses cell towers. While I haven't tried this program specifically others I have looked at don't really have pin point accuracy in determining location using cell towers. They might be accurate to a mile or two radius around the tower(s). That isn't very accurate IMHO and can cause issues with some programs like the real time traffic program I use all the time when I am in the car. Not getting a good connection for the first mile or two (or last mile or two) of my commute is unacceptable in my situation.
Also, in my case, my workplace is 1/2 of a mile from a intersection of two interstate highways. Is is a spot where traffic is always bad and I rely on the real time traffic updates. I pass through this interchange all the time - not just when driving to/from work. If it switches to wifi every time I'm driving on the highway near my work place, this obviously won't be acceptable.
I'm going to try this program and see how it performs. But this was the reason for my question above.
PS - it really is too bad that you cannot kill an application with Tasker anymore (thanks Google for trying to "protect" me from myself). It would be really easy to create a task that would kill the Y5 service when the phone was car docked and turn the service back on when it was removed from the car dock. This would fix any potential issue I would have with this program.