I was around a Clinton visit in my hometown once when he was POTUS, & I was monitoring SS plus the locals.SS was the usual secure plus very low-power clear voice inside the 'bubble' on a couple channels, while local LE was clear-voice on a local mutual-aid channel. Local command officer A got on the channel they were using & told local command officer B to call him on the cell phone immediately. I noticed some excitement to the tone of voice, so I decided to investigate.
I was able to find that cell phone conversation pretty quickly, and it turned-out that ol' Bubba was going to make a no-notice/unannounced stop at a local Coney Island joint along the planned motorcade route in that city (hey Humpty or Wall-Cloud Willie, is Abe's still there?) & would be arriving there in about 20 minutes. SS advised the local command officer to NOT relay that info out over the radio. It was just a head's-up, since the motorcade would have passed by that location anyway.
That intercept gave me tactical intelligence that, had I any interest whatsoever in meeting Bill Clinton, could have allowed me to get to that restaurant in advance of him & his motorcade, take a seat & order some food, and then act surprised when he came strolling in to shake hands with the other customers & eat a hot dog or three or four. Since it was a 'secret'/no-notice visit, SS wouldn't be screening anyone who was in the restaurant prior to the principal's arrival, since theoretically, no one but him & a few cleared personnel knew he'd be stopping there in advance. If I'd had sinister thoughts, such as if I were Monica Lewinski's father, well, I could have wiped my hand on my ass before I shook his hand... Wow, what a proud photo of Bill & I that would have made!! Now I'm sorry I didn't rush to my car & go to the restaurant...
Same sort of thing happened with VP Dan Quayle a long time ago, this time involving a grocery store. My girlfriend & I made it inside about 30 seconds before his motorcade pulled up, & were able to shake his hand, plus I asked him if he was going to be buying broccoli (it was right after GWB got all the publicity because he said he doesn't like broccoli (see:
Bush, George quote - I do not like broccoli. And I haven't liked it since I was a little ki... ).
The local public safety comms have always been a vulnerability for SS motorcades. It's discussed by the Advance agents in the planning meetings with the locals. Not much that can be done about it, other than to limit the amount of info you give to the locals until they need to know it, & give them info about alternate routes & other contingencies on paper so that if something occurs, there doesn't have to be a lot of non-secure specifics broadcast out. The local motorcade lead car has an SS agent in it with a secure radio, too.
