Thanks for sharing this! Dealing with palm-press trackpad jumps on a ThinkPad is incredibly annoying, so this is definitely a welcome for anyone running NetBSD on a laptop.
The finger_high sysctl trick is a pretty clever workaround to bypass the driver interpretation entirely. One quick question on how you're handling it: since writing to sysctl knobs usually requires root, does the daemon have to run with elevated privileges? Running an X-centric tool as root can be a bit sketchy security-wise, so I'm curious if you've looked into separating the X11 listener from the actual sysctl call, or using a small suid helper.
Also, out of curiosity, did you run into issues trying to use user-space tools like xinput or wsconsctl to toggle the device? I know if you're using the generic wscons driver it tends to multiplex everything into one stream, which makes isolating just the trackpad a massive pain—assuming that's why you went the kernel route.
Either way, nice work getting this up.
Cheers,