Probably not a new issue, but technology is lowering boundaries again. Garmin has released a new GPS unit - garmin edge 800 - everything to verbal directions telling you which way to go.
Do you use these things? Have you posted a trail and seen an increase in visitors? Are they litter-bugs or what? Are they trashing your ramp lips and cutting corners? pushing the limit and angering land owners? - in short will or have public GPS route postings benefited or damaged your local trail.
GPS helps with some trails which are difficult to find for people from out of town, it's better they know where they are going so it's a good thing. the trails we don't want people on, we don't talk about outside ourselves, so GPS doesn't really matter in that case.