Unspoken Rules?

In baseball, there's what is known as unspoken rules. Examples: don't steal bases when you are up 4 or more runs later in the game; in the past a brush back pitch was expected if the batter preceding the present hitter blasted a home run; and hitters don't flip the bat after blasting a home run showing up the pitcher. When written these sound arcane. Does table tennis have unwritten rules? I believe so.

With Covid19, I've been watching LOTS of table tennis on YouTube via my subscriptions (including Table Tennis Daily) and searches. Part 1 and 2 history of Jon Waldner (3+ hours), Timo's matches, play and tricks of Adam BoBrow and much more. I've noticed the letter of the law regarding serves in serious play, even in championships matches, is not adhered to. It's common to see ball tosses be directed in multiple directions and never challenged. Most all other rules seems enforced. It seems to be a gentleman's agreement between the players to allow the ball to be directed rather than an non directed upward toss. I've not attended high level matches as yet. Is the protocol there the same? The YouTube videos I've watched show the "unspoken rules" exists.

And, what about players who serve from the side of the table rather than from behind. No one would be in a position to see if the ball was above the table or behind the table. The opponent will see the player clearly ahead of the rear line but poor line of sight with the ball toss being on the table or behind.