Here's an example I recently saw (the actual approach is probably different, but the concept the same). Since @olasek is based in Oakland, let's do the KOAK ILS or LOC/DME 28R. Loading vectors to final in the GNS boxes will give you a straight line extending outward from CUVSA but you will not see any of the other fixes. A simple "proceed direct GROVE, maintain 3,400 until established, cleared for the approach." Will have you scrambling to reload the approach so you can get there and meet all the pre-GSI step-down fixes (or flying it like Jerry W ). I saw that one take place for the first time in 2009 when I safety piloted for a friend with G1000. It's pretty much what led the FAA to add the AIM recommendation to not use VTF. What the GTN series does different is, loading VFT will show all the fixes on the straight line between NAGVY and the runway. That solves a lot of the problem - "Direct GROVE" just means hopping into the flight plan, selecting GROVE and hitting D→. This has led some instructors to forego teaching "load a logical IAF along your route of flight." Problem is, if yo are coming from the southeast, all it takes is ATC deciding, "proceed direct CYMBL" to produce the same scrambling result. Been there. Seen it. And it's a potential issue on any approach with fixes outside the extended FAC - like every approach with a T-configuration).