You have discovered that when in a crowded area, you sometimes get a stream of unwanted text messages. The messages end when you leave the area. Which is the BEST description of this attack?

In the case of the attack you have described, the attacker is sending unsolicited messages to your device, but they are not gaining unauthorized access to it. Therefore, the best description of this attack is bluejacking.
Bluejacking is a method of sending unsolicited messages to Bluetooth-enabled devices. It is typically done in crowded areas, where the attacker can send messages to multiple devices at once. Bluejacking messages can be anything from simple text messages to images or videos.