B-CHOPS please do not assume that GA is the only culprit. Please refer to official statistics for airproxes, level busts, unauthorised entry into cas etc. and you will see that commercial air transport and military are guilty of such things. Your "free for all" is very much a misnomer and very few pilots would treat class g as such. Please also be aware that by a very large margin GA accounts for the majority of aircraft movements in the UK and therefore places such as Doncaster, should it aquire class D will do so at the expense of the MAJORITY of airspace users.