I've bought two tickets through 1st-air.net and both times the tix involved a hidden city situation (involving Canada). One time they had me starting in Canada and then ending in my desired ORD termination point. The other time I started in ORD and then (was supposed to) end in YYZ. However, there was nothing in the tickets that were sent to me indicating either Canadian hidden city. The only way I found out was by calling to confirm my reservation and then had the phone rep. read off the Canadian city as part of the reservation.

Truly a buyer beware situation.