Lol ... well since I'm the "wristband man", let me at least put in a vote for that. Just one clarification ... in the system I've used, the coach uses a 3 number system that could be verbalized, but which I personally prefer to just hold up my hand and give. I don't like to draw attention to either myself or to the numbers. Those numbers then are "translated" by the players using their wristbands. I had not thought of it before but, as John says, you could also touch body parts that could be translated as well, though my only issue with that is that invariably I would like scratch myself or something and confuse the players!
The thing with the wristbands is that the coach has several options of number combinations they can use for each signal and can alternate this all of the time, not to mention that you can also easily change out the cards every so often, including as much as every inning it you wanted to, making the signs impossible to steal. In my system, I give the coaches 3 different sets of signals upfront to work with. You can also buy the software/license to do this all yourself before each game, but in my research, I found it to be very expensive for the system and potentially the wristbands as well, and I don't think that most coaches will want to pay for or bother with that other than at perhaps a D1 college level.
I really think you're going to see the use of wristbands increase significantly over the next several years, much like it did in football. I've introduced the concept to a couple of high school coaches in the last year, and I know they will never go back to the old system. While it could happen in baseball as well, my sense is that a lot of coaches there will want to stay with the touching of body parts, as it's more traditional ... just my opinion ...
