This is very common in the states for domestic flights at least. I flew a few trips out there on US Airways and United and the First Officer (usually) was always at the flight deck door saying farewell to the passengers on deplaning. These flights were all 737 / minibus so boarding / deplaning was always from 1L, not sure if this would work on a 757 where 2L is commonly used.
Certainly a nice touch though, albiet perhaps a tad unnecessary.