yeahthis is all true, but a good tech can mount your bingings free handed just as well as any jig.
I mounted my skis last week, my urban skis of course, using this site
http://www.forskiers.com/articles/8.asp i had a thread about it too, just watch out when you mark the drill bit with tape, it tends to push the tape up when you drill, so measure twice cut once. So far they turned you really well, everything is perfectly lined up, ive hit 2 urban rails, a couple ledges and my rail and they held up fine,