The problem with the unplanned flyby is just that. It was unplanned. It appears to have gone well but.....how many circuit breakers were pulled to avoid GPWS warnings? Did he get them all or was there distractions during the flyby. Did the airline insurance allow for airshow manoeuvers? Probably not. Did the Company Ops manual allow for unauthorized airshow stunts? Probably not. Did he ask the passengers in the back if they wanted to be part of his flyby? Don't think so. Was he going to try a banking peel off turn like the Air Portugal pilot did on the famous A310 stunt? Maybe or maybe not....we will never know because it wasn't planned. When you fly for an airline you are not flying for a flying club. These are expensive machines, being flown at high costs as part of a serious business plan. There is no room for individual impulsive expression. It sometimes ends in disaster. Fly the aircraft according to your flight plan and deal with unplanned events using the training provided and the experience in your background. When you do unplanned things you are asking for it.