I've had them fly about 400ft below me when I was just outside Luton zone. Very pretty, heard on Luton frequency that they were coming and we managed to avoid each other. Bear in mind that there are 8 (?) of them looking, there's only one of us in our a/c.
What do you want us to do - all hit the deck as soon as there's a NOTAM that the reds are out today if we are within 10 miles and an hour of their route?
We are all in uncontrolled airspace, if they need IFR only, they are welcome to go higher and miss all of us by a long way. They get FIS or RIS if they want it.
I think part of the Red arrows display is flying low between points so lots of people get to see them. They must be used to seeing us GA's floating about.
Infringing a display is completely different, but complaining about people being in uncontrolled airspace is a nonsense!
BW