I truly believe that displaying of commercial aircraft should only ever be done by approved display/test pilots. These people will be well-versed in all the issues and have no doubt practised the routine in the simulators many times
.
IF this was conducted by a line crew (base/training captain notwithstanding) it was, at the very least, cavalier and bordering on the criminally insane.
For non-test/display pilots on the day I believe the adrenalin pumping may cause good sense and caution to be forgotten and margins eroded.
They got away with it here, let's hope they learn from it.