I've just handed my logbooks in to the CAA with no signatures (the last half is a hardcopy of my e-logbook, so v. difficult to get Capts to sign).
I've asked the question of a few of my colleagues and the consensus seems to be that if you work for a reasonable sized commercial company they will have an idea of your expected hours and as long as you aren't cutting it too fine they don't have a problem.
If you are trying to upgrade with 1500.1 hours they might want to check a bit deeper.
I'll let you know how I get on...