It’s seems straightforward to have random testing of the balls throughout a game. All the umpire needs to do is ask the catcher to hand it over. If they’re suspecting this is happening and they’re not doing it, it’s intentional.
Does the public find the defense heavy game more enjoyable? I’d imagine more hits and homers would liven things up.
The point remains the same. Ideally, you'd be contacting the ball much further up the bat. There still might be some transfer, but probably not a whole lot.
You could also collect every strikeout ball and put them in a bag marked by pitcher for analysis. After a few games, you could quite easily see which had uncharacteristically higher tar on them versus baseline. That is, if the MLB actually cared.
Pitchers are putting the substance on every ball. Nearly all strikeouts are caught directly by the catcher, and the 3rd strike is the hardest to get, so it would be a very good sample indeed.
Nearly every ball touched by a bat is tossed out of the game--foul balls, balls in the dirt, balls that get tossed back by the pitcher. Games typically use between 84 and 120 balls. It would be trivial to detect if the ump did a check on every ball in play or after random outs. It's not like the umps can't see the same action the batter sees.
Does the public find the defense heavy game more enjoyable? I’d imagine more hits and homers would liven things up.