Nice mod!
I expect that given there was a nice, clean place to cut, you will have no problems - still, I'm curious how you measured the differences (and lack therof)?
I would expect that exposing more of the sense line to the edge of the pcb (where the second row pad was cut through) would result in less tolerance to external noise, for example. I would have nipped those traces a bit away from the edge, just for luck, presumably - since I don't have any sort of testing setup to generate and measure levels of background noise. :(
I'm not suggesting you didn't test well - I'm just a bit wary, as people tend to be a bit optimistic after a major mod. I had a hilarious issue a few years back where my sense would get flaky after a few weeks to a month or so of uptime (mostly during the spring or fall, when the temp near my desk was exposed to large enough temperature changes as the weather, heat and AC changed.)
Fun mod, though reminds me that the other week I was discussing (on irc) that I had noticed that a 122 F can be cut nicely along the jagged strobe including - "F" to make a bizarre 60-key left-handed gamepad of some sort... right hand might be a bit more aggro, though, if one wanted to make a split keyboard out of two 122s.
Both your cut, and the one I was thinking of, preserve the strobes on the backside of the board, and merely shorten the sense lines.
As to whether things would be so cuddly if you removed the ground surrounding those lines while they were still active, or partially active, woud likely be a more representative test of whether the ground lines on the F is important with the xwhatsit. :P
Best of luck, hope your next project is successful too.
dfj
