Or even better, film them. I got a request from beginning game designer Sara Pickell, who is looking for footage of your hands while playing World of Warcraft or another MMORPG. I'd help, but I don't even own a video camera.
The request makes me wonder whether other game designers looked into how ergonomic their keyboard layout was, and how much button mashing it involved. I am good with keyboards for the rather ordinary use of typing (I type 50 words per minute), but some games get my fingers all tangled up. For example I found the combos in Age of Conan hard to type as fast as I wanted, and ended up putting them all on macro keys of my G15 keyboard. For WoW I'm not using keyboard macros at all.
How about you? Are there MMORPGs which you find easier or harder to use by keyboard than others?