What's a call record? Like a single phone call or an SMS? Pinging the tower doesn't count, does it?

Why not? It's perfect way to signal.

nvm, the article mentions it. cell phones check in with the tower while they are on, which is a way to track where someone has taken their cell phone. afaik, there's very limited privacy protections around this in the US because they are considered the business records of the cell company.