BS. The technology exists but I doubt the DoD is spending the $ to deploy it for VIP TFRs. If they did, it would provide even more reason to question the millions of dollars it would take to negate a threat so marginal as a light aircraft.
Depends on the VIP. Even within VIPs there's a pecking order, can't be frivolous with all that money, ya know. Only some are worth it.
A "standard mission package" of assets for one VIP, might be completely different for another.
Judging by the world-wide radio monitoring folks, TACAMO aircraft are usually up and in the area too, a day or so in advance of the President and often the Veep... not regularly for anyone else, and they rotate from VIP TFR to VIP TFR in different areas of the country, with multiple aircraft swapping coverage times.
Gotta have Comm...!
And once in a while someone will notice they're supplemented with traditional AWACS.
Of course, all of that takes a while to confirm... one has to merge the radio monitoring folk's info with the visual spotter folk's info, so really you only know if it was the aircraft it SAID it was, a day or so too late. By the time you know what was there, it's gone.
There's some pretty dedicated (bored?) mostly-anonymous folk that post all this stuff on the Internet in real-time. Sightings, radio chatter, etc.
But... that said, the U.S. Military is pretty good at disinformation when they want to be...
Presidents have shown up in countries no one expected to see them in before, and will again.
Not just the TACAMO folks are nearby... there's some other alphabet soup that's not public. In the end, since they love acronyms, they should just call them "BAWLOFBOTS".
(Big Airplanes With Lots of Funny Bumps on Their Sides.)
http://www.tacamo.navy.mil/ - for those interested in the official public info on TACAMO. (Never seen a military squadron that didn't do "more stuff" than their official website said they did...)
You gotta love jets that can trail VLF long wires to talk to submarines, and have *plenty* of radio toys aboard...