I first read the conspiracy theory about the Covid vaccines injecting bluetooth transmitters  in August and dismissed it.  But the rumors kept resurfacing so I installed a bluetooth scanner and tested for myself.

And I got quite a shock.  I've done five test runs in three locations and there are a large number of "unknown devices" that I can't explain.  This test run was at a bar with 200 ft of open space on three sides and an empty strip mall on the fourth.

Here are screenshots of the Bluetooth RSSI Analyzer.  There's 60 devices in these two screenshots which rose to 75  after I took these shots.

There are 23 devices with a "cell phone" icon, which could represent real phones as the bar had about 23 people.   Which leaves 52 devices to explain.  Assume one headset per person.  Maybe a couple of fitbits and watches.   There's at least 20 devices left.  

I used three different BT Scanners and got the same results.  Very few named devices appeared but many "unknown" with invalid manufacturer MAC addresses.