Some people raise the issue of "brailling" tiles and refuse to play with etched in tiles, such as those that which commonly come with a store bought version of Scrabble. Is this a big deal? Have there been issues in the past with "brailling" in top-rated tournament play? Unless if someone is super good at it, I would imagine it would be easy to see if someone is taking too long to draw their tiles. It seems like too big a fuss for me.
Apparently there is enough of a concern, because according to the latest tournament rules:
In addition, to keep players from swapping tiles with adjacent games:
My finger sensitivity isn't good enough to tell tiles apart, but I'm more than certain that people with better-than-normal finger sensitivity could easilty tell tiles apart.
Etched in tiles can be readily rejected by feel by many players. Picking the right ones is harder than rejecting the Q or Z you're not going to use with your other tiles, but is still a huge advantage.
I can, with inset tiles, often tell when I've got a Q or a Z. Or, I used to be able to; it's been YEARS since I've played. But against friends who couldn't or didn't, I was able to get more tiles I could readily play.
Moreover, it's not a hard skill to practice and to learn, and may not even be consciously done by some players. Even some painted-on-letter tiles have sufficient texture differences to be felt.
So, yes, there is a good basis for the rules against etched titles. It's to keep the game about winning with random draws, rather than feeling for the tile you want.