Yes and no. We have to "check-in" prior to the trip NET 36 hrs and NLT about 12 hours prior either via phone call to scheds or via CCS (our computer interface). If you don't do this scheds will attempt to contact you to check in and if they fail to reach you, you'll lose the trip. I think it is more of a "hey letting you know I remember I have a trip to go fly". Capt and F/O both sign the initial dispatch release for the pairing via CCS and Capt signs all subsequent releases for the pairing. F/O signs initial only as a "I am here, all my stuff is current".