On the Saab, most of the captains will take unlimited. Thats 30 in the back and one in the cockpit. On the 170 I don't know the policy, but I am sure it is probably the same, the guys that I have met from that side of the fence are pretty cool, and they mostly commute, so as long as you get by the gate agent, that is usually enough.
We have no official published limit.