I was allowed to sew when I went looking. I only looked at the two local shops, but they had fabric for me to "play with." (I had brought my own also, just in case.)
I was an unusual case, as I was looking for a very quiet machine, and my husband had fixed up a device that measured the ....oh, sound waves, I guess....not sure what it measured. I just know that when pointer pointed to a higher number, it was louder. We were looking for a machine that wouldn't interfere with his amateur radio equipment, which is in the room next to my sewing machine.
The sales clerks were very nice and no one fussed about this extra test.
This was 3 years ago. I would not have bought a machine from a place that wouldn't let me sew with their machines. The sale prices were right on the machines. I didn't ask for a better deal, which isn't in my nature anyway, because the sale prices seemed good, not too far off of what I found online.
Dina