Crazy thing: my friends who run a high traffic coffee shop just found this thing under their bar. It turns out to be a super cheap Chinese Bluetooth LE beacon. 
Here's the model. $1-$15 on Alibaba, lasts up to 10 years on two AA batteries, can broadcast an advertising URL using the "Eddystone" standard. minew.en.alibaba.com/product/608041…
I was able to connect to it, and the URL that this particular one was broadcasting appears to have been some sort of student loan scam. So, basically this is an instance of physical, location-based spam.
Thanks to @emerose and his security Slack pals for for helping me figure this out!
Update: looks like Google is discontinuing Android support for "nearby notifications." android-developers.googleblog.com/2018/10/discon… /ht @roessler
@roessler Oh, here’s a screenshot of the config info (including the spam link URL) in case anyone is curious.
Update: this thing has been sitting on my desk running, and one of my co-workers with an Android phone finally just got the spam notification.
