Attached is your route. Direct doesn't take you through the SFRA unless you started at a point much further to the east.
Can you return to airport of origin under lost comms? It's not a 7700.
Proof that it's been a while since I've done the route. But it does take me through that unfavorable area.
As for returning under lost comms, again, this is the practical side of it. For one, if I've just departed home and my comms are busted, why am I going to fly 450 nm so I can be stuck and try to repair them somewhere else? That's a 91.3 application, and I'll deal with it once I'm on the ground.
The one time I did have a total electrical failure/lost comms, I was able to get ahold of ATC eventually, canceled IFR, and told them I was going to divert and fly back to my home base. The guy gave me a phone number to call, the reason being that he wanted to make sure I got back safely. I called him when I was on the ground and thanked him for his help.
Yes. ATC should not give you a clearance that will go through P-40. If they do, and you see it, don't accept the clearance. If you both screw up and you don't see it until after you lose comm, 91.3(b) applies. And if you still don't see it and you get shot down, your family can always sue under the FTCA.
So you're telling me that you've never been given a clearance at your origin that won't take you through an area that you shouldn't fly through? That would be quite surprising given that I received them regularly flying in the northeast.
Neither the SFRA nor Class B airspace are "restricted airspace." That term is specifically defined, and does not include either one. Further, an IFR clearance constitutes approval to go through both.
True on the SFRA, but from a practical perspective they don't want you flying through it unless it's where you're landing, and given the heightened security I can imagine that a "lost comms" in the SFRA wouldn't end well. Either way, going over the President's hideaway isn't kosher, either.
As I said, the practical side of it is you can get clearances that will take you through areas that they won't let you fly normally.