Actually, if you are, even only face-saving officially, part of an operating crew your flight duty time starts at the report time of that flight. Simple EU-OPS rules. Therefore using something like that could lead to more than pointed questions after an incident. During normal operations nobody cares.
My company allowed us to fly for free until around a year ago. We would just print out a ticket at any computer and show up on checkin. However we were not part of the crew, just normal standby passengers with full passenger rights. The company paid for the security and airport charges and still continous to do so until now, however nowadays we have to pay the usual Z class price for the ticket, which on the other hand allows us not to fly standby but on a confirmed fixed booking for only a minor price increase.
Commuting from and to base is normal for many flight crews, so nearly all airlines have some scheme in place to allow that, however they should take care to be legally on the safe side.
Last edited by Denti; 12th January 2013 at 17:43.