I have been to approximately 70 tracks world wide. I have seen safety crews from excellent to basically clueless. I have marshaled, raced, wrenched, worked race control, been a steward, spectator, tech inspector and had training on fire fighting from Cdn Air Force. I am now in the media.
As I pointed out there is currently the technology to advise the drivers instantly. F1 uses it. There is also the technology for race control to limit the speed of the cars. No one uses it yet. I can see it coming in F1 very shortly.
At Valencia 9, yes 9, drivers received penalties because they did not slow sufficiently or quickly enough under the Safety car.
Just because it has not happened does not mean it won't. Not every circumstance can be controlled but IC, and some other sanctioning groups had better seriously review their procedures.
Because of the basic track design ovals are far easier for safety equipment to get to an incident. Mostly they are also shorter. The Glen is 3.4 miles.