I'm less talking about burning a line for yourself to use and I'm more talking specifically about burning a line at an angle that either your competitor cannot play, or across their line (and that you also do not plan to play). It is also unfair when a lane comprises of more right-handers than left-handers (or vice versa). For example I've seen Belmo practicing very deep and totally screwing up the left lane heads for somebody like Parker Bohn, seemingly on purpose.

Pulling out a urethane ball in practice to do this and never throwing a urethane in the matches is proof alone that it is not actually practicing.

There is no perfect comparison, but you could compare it to cyclists, racing drivers and running teams strategically using their teammates for aerodynamic advantages in solo races. I personally would compare it with cricket bowlers picking holes in the ball with their fingernails in order to effect an unusual bounce, which is now banned.

In my opinion you should not be allowed to practice more than three strike throws with a ball you do not use in the match/es for strike throws.