Were you using a tether? The more recent garmins have a tether, figured the 530 would too.
FYI:
You can do a Lost Name/Number when the device starts up. Info @ https://www.dcrainmaker.com/2013/08/display-number-garmin.html
"Increase your odds from none to slim" ?
As someone who lost a Garmin 705 and a hiker found it, used the gps files to figure out who I was, and the contact me and return it, I'd say chances are pretty high if someone finds it.