In Russia it was the normal procedure
The flight deck crew would arrive on board often as the pax were boarding, and certainly pax were told to remain seated until he flight deck crew had departed.......
Actually I would have expected a standing ovation, but then perhaps not......
The last flight I made in a Yak 40, was deserving of the ovation, as the weather was "not good", and the 2 adf approach was awsome......I would not have been happy on a Cat 2 ILS......
So in future, with the high crew security checks, perhaps they will continue to arrive after the pax.....
Bumz