I mean... Do you really need ATC to tell you that you're about to (or have) bust controlled airspace? Really?
I mean accidents do happen, but today, with increasing numbers of garmin installed as 8.33khz replacements, and ever increasing number of people using skydemon with GPS receivers, it seems hard to do so by mistake. I remember someone talking to Farnborough west, who happened to have strayed 3 miles into the LHR zone, being told "turn south immediately, you are inside controlled airspace", and the response from the pilot was "Oh we'll just head west for 1 mile" - i mean... It did make me laugh but the stupidity of this pilot was clearly even beyond even the help of ATC!
I'd like to just point out that if you have a mode S transponder installed, the controller not only knows your altitude, but also your registration. So if you happen to use the listening squawk, I see no reason why ATC would treat you any differently to anyone being provided a basic service. I have occasionally been passed traffic information with nothing more than listening squawk. Which in my mind was pretty damn good! I have also heard ATC call for "plane just south of Bewl Water on listening squawk, say callsign", I mean it did take 2 tries but the pilot did respond! So the system, CAN work...
Sure it doesn't increase our situational awareness, but does it really reduce it? Quite often on basic service, it really doesn't. Someone calling for a basic service just south of Sevenoaks, saying that he is going to Lydd, does not necessarily mean that s/he'll go in a direct line to Lydd, s/he may well go via Beachy Head for a spot of sightseeing! And s/he may not call again until reaching Rye for QSY (ahem! Sorry meant frequency change!) to Lydd.
And to those saying that it is pushing people to use ADS-B, well I don't know, ADS-B does increase your situational awareness quite considerably! Sure, right now it is very expensive to install, but perhaps in a year or two it'll drop in price, and become much more commonplace to have both ADS-B IN and OUT!