How about at a class C with 737s? Would they be delayed by unknown traffic less than 2000ft over the airfield? That's what the OP is talking about - 3 airliners, which are likely to be 737s at East Mids.
The Class D airport I mentioned is directly underneath Class B airspace used by airliners and military traffic, with a total of about 2500 operations per day for all the airports combined. I have never heard of operations at any of the airports in the area being delayed by non-communicating traffic.
I could however relate some stories about people flying uncleared into the local Class B, it happens every day, including a guy I knew (now sadly passed on) making his last ever solo flight after 70 years of flying. He was told on the phone not to do that again - and decided he wouldn't!
I occasionally fly a non-transponder equipped aircraft directly over the primary commercial airport within the Class B area, without being in radio contact with anybody. At about 3500 ft directly over the airport its legal. I prefer to do it in an Electrical/Mode C equipped aircraft so they can see me, and know my altitude, even if they specifically don't want to talk to me.