Couple of interesting twitter threads on this from Tyler (The Drive). He suggests this has been coming/happening for some time. https://twitter.com/aviation_intel/status/162414986417840128... Also that we are seeing a lot more now because we have turned down/off the filters on the radars. Which means also we can expect a lot more false positives. https://twitter.com/aviation_intel/status/162461466198661120...
This may be true, but it's awful hard to get visual confirmation and then shoot down a false positive.