Honest question: Is using Tor not a risk by itself in Iran? I wonder if this doesn't pop up under surveillance mechanisms as conspirative behavior and may trigger focussed surveillance, which is hard to get out of.

But maybe so many people in Iran use Tor that it's not very outstanding to use it? I remember there were stats on that published on the Tor Project Website...

Edit: To answer myself after 5 minutes of thinking: Of course there are bridges, too. I guess they don't appear as suspicous as regular entry nodes?