Technically, there is a one JTA bus line currently using a GPS location setup for cellphones. I think it's from downtown heading east towards the beaches, maybe along atlantic blvd. This is also in its trial phase and if all goes well will roll out to the rest of the system...eventually.
The key word is 'trial period'
If ridership is high, the service can be expanded. If people are apathetic and don't ride, then the service goes away.
It only took three years to get this far after so many have complained that a service like this wasn't available for so long... so its time to put up or shut up 
I get the "trial period"... but it seems to me if they really wanted a fair trial... it would be every weekend during that timeframe.
I see it as an advantage. Being just one weekend a month I think everyone will be amped up to maximize utilization, either to make a point to JTA or to just experience it for the novelty of it all. The difficulty will be in maintaining a decent ridership if the service IS provided every weekend.
I'm making a point to be there for both reasons I listed above, but if it becomes a weekly service I'd still probably only use it once or twice a month since I don't live in the area.
