Let's get one thing straight. GPS has been part of the PPL sylabus for 10 years or more.
However, the one issue common to a large number of lateral infringers is that they did not apply an appropriate margin of error to the technique they use.
How many people plan thei VFR flight at a level that is for example 1000ft above all obstacles within 5nm of track so that they will have suitable clearance above the hills. masts etc that are along the track even if their navigation is not keeping them exactly on track.
These very same pilots plan their track to pass within perhaps 2nm of a control zone and can not understand how they could infringe.
Approved installed GPS units are RNP 5 in the enroute mode and thus are only guaranteed to keep the aircraft within 5nm of where they say it is.
Therefore, unless pilots plan to miss controlled airspace by a minimum of 5nm they have to have something else to use which enables more accurate navigation eg a line feature etc etc especially when visibility is not good.
Far too many PPL's measure a VOR radial from a 1:500,000 chart that misses a control zone by 1 or 2nm and despite the fact that the VOR is some 20, 30 or more miles away make no allowance for either the system errors that can cause them to be in the zone even when the VOR says they are not.
Find me a bit of PPL, CPL, IR, ATPL training provided in the UK that discusses in any depth the various errors in the various navigation techniques and facilities i.e. just how accurate will DR be with a fix every 15 minutes. How much more accurate with a fix every 6 minutes etc - except GPS which of course where the errors are explained frequently the pilots reliant on GPS don't believe that the error can ever me more than a few feet.
Personally I always have my map on my lap and cross check from GPS,s and other nav aids to the map so should they all go phhutt I can put my finger on the map and be sure of my location. One thing my 296 is good for is naming towns and villages that are just a blob on the 1/2 mill map.
Clearly indicates what is a big part of the problem. Find me the bit of the above quote where the expected position on the map is crosschecked with the actual position on the ground!!!