Like many basketball plays, there are usually three officials and 10 players. Not every player can be watched simultaneously and this certainly applies to a jump ball, especially with one set of official's eyes on the ball. Yes, we only
watch for common violations or will pick up extreme violations. Not sure what one poster meant about not crossing the division line
ever as we are all familiar with someone stealing the tip by directly crossing the line, usually done when there is one tall and one short jumper. See example here at 20 second mark.
https://www.youtube.com/watch?v=KHBpR8Y-U0M
But again, notice that this is an extreme breaking of the rules not one based on a slight angle of jump landing. I have had this twice in my career, one being crossing the division line and the other being leaving the back of the circle. Sometimes there are rules in place that are created to prevent egregious/rare/extreme acts but their wording also applies to lesser acts. Clearly, the jump-ball wording in the rule book needs amending. Of course, then we sometimes end up with rule books that are too big. The tax code is a good example of this, lol.
Bottom line is that there is nothing to officiate in the OP. Play on.
(Indeed, thanks JRUT)