Recently, in our area, a guy was following an older woman in a store parking lot. She triggered one of those personal siren alarms and he left the scene. My wife was interested as she does carry an OC (no chance for a gun with her). Now, I've been through all the usual arguments, challenge the guy - help police, etc. Deploy the OC if he is a real threat, etc.
But is there any experience with these personal alarms? I could see in the big parking lots of our rather nice stores, such a noise maker bringing unwanted attention. On a trail with lions, tigers and bears, not so much. I did read a story once that in Chicago, IIRC, a little girl was kidnapped, she trigger her alarm, no one helped, and some neighbor buried the alarm to shut down the noise. She was killed.
We do get the guys who run out of money for gas in the parking lots once in awhile. They home in on the elderly or Moms with kids.