that is kind of a different situation though, in a bar full of normal, "people", people who don't see a lightsaber ever, and all of a sudden one flashes to life across the bar and cuts some gun wielding maniac's(Zam) hand off, everyone is going to take notice, and the music will stop.
Its not that the Jedi show up, and everything comes to a grinding halt, it is the lightsaber that got everyone's attention. The only one's that can tell the difference between a force user and a regular person, is another force user. They can sense that another force user is near. Other than than, you could be walking calmy by the Senate building on Coruscant, and pass someone in a beard, and never think twice about it, never knowing that that person was just Obi-Wan, and could mind trick you to throw yourself into oncoming traffic.
The very existence of flamethrowers proves that some time, somewhere, someone said to themselves, "You know, I want to set those people over there on fire, but I'm just not close enough to get the job done." -George Carlin