It does happen, like the mod said usually to drum up business. It’s a bad idea for SPs to do that though, unless you’ve given permission.
I’ve been sent the “how are you?” texts, the unsolicited nudes, the filthy dirty talking texts, the notifications of an STI exposure….all of which are bad. Nothing more than an innocuous “Hi” to start a convo when it’s safe, that’s the only acceptable unsolicited text.