Rule 2.6.4 (...and behind the server's end line...) is the current disaster in table tennis. 80% of all top players sin against that and no referee has the guts to say anything about this.
Yes, correctly observed that this is what happens at the pro level and even in sanctioned amateur tourneys the few times there are umpires officiating the match.
I will say this... you need NOT WORRY when Der_Echte is on the job.
I have zero empathy for illegal serving and do not care what anyone thinks about me calling the serve by the rules... which is that if the umpire is not convinced that the serve was legal, then it is illegal.
I care not what jokers say. I am not concerned if a player, coach, fan, or anyone want to threaten me and get physical with me. I will handle it with decisiveness and finality... very suddenly.
The problem is, that when an umpire actually enforces the rules, that umpire will not be a match umpire the rest of the tourney, maybe the rest of the year, or decade. Such an umpire will be blacklisted faster than you can spit.
You can also count on Der_Echte not being concerned with that either.
Unfortunately, ITTF umpires like their badge, the ability to travel and eat for free, even though they get paid zero to peanuts less than minimum wage, ITTF umpires tend to want to keep their umpire badge.
In a recent seniors tourney (a USATT sanctioned tourney) I sat down in the score keeper table to be scorekeeper for a doubles match... I ended up professionally presenting the match and umpiring. I was exceeding my authority by umpiring the match, even if it was a proper and professional execution of duty. Being a trained and umpire was irrelevant. I was supposed to shut my mouth and flip the scoreboard. Somehow, something was defective with my mind on my decision to professionally umpire the match.
A dude on one doubles team had a blatant illegal serve to team Ju Mingwei... dude had zero toss and served the ball fast right out of his hand to Mr Ju. I raised my hand, called let, stated the ball was not tossed 6 inches and provided the visual sign. Seconds later, dude served again... the very same fast serve out of his hand. I raised my hand and called point for team Ju Mingwei. Mr Ju had a tiny acknowledging smile, like he never saw an umpire call an illegal serve.
Both the player and dozens of the crowd watching were in shock at the gall of the umpire to call an illegal serve... and count the point against the illegal server... after all, such a thing is very normal and accepted in the club and by those of the player's ethnicity/age/culture at their play level.
That player's partner served next time around... she served it with an entirely backwards toss right onto her racket... I immediately raised my hand and called point for team Ju Mingwei. The crowd was in shock again. they sent their club president to replace me as scorekeeper.
Very soon afterwards, I was replaced as scorekeeper. I got the Trump treatment... Youuuuurrrrrreeee Fired !
I never had such a grand time ever being fired in my life. I spent the rest of the match joking with Ju Mingwei's translator about how umpires are afraid to call illegal serves (and be blacklisted) and how I had to pay the price for calling the illegal serve illegal. I wasn't getting paid and I had no connection with that venue's club, so I was not concerned, nor would I be if the situation was different. It was easy to laugh that one off and have a good time over it.
Before my next visit to Table Tennis America TTC, I will need to learn the Chinese phrase for REPLACE THAT UMPIRE ! If I can learn that and say that to Ju Mingwei as a form of saying hello, I think that would be a riot.