Was it mostly Iranian companies there? I assume you can get instruments from elsewhere. I don't look look much at folk instruments, but there is a shop in London that has all sorts and maybe some are from Iran.
At the guitar show I go to they make everyone turn off the amplifiers on alternate hours to give people a break from the noise. I saw a lot of drums at your one though and they will be noisy.
I think there were more Iranian companies there, I see, so they even had Iranian instruments in London, interesting! :)
While we were there, I think it was a busy hour, but later at night, they even had some famous artists performing on their stage. Unfortunately, I missed that part, and I think they might have a similar rule about giving people a break from the noise.
Especially the percussive parts really needed to be managed, and I agree with you.