It’s just another scare tactic, one which saw heavy exploitation in the COVID era. I personally tested presumptive positive once: they treated me as though the test was positive and prohibited me from receiving medical care. In fact it was explicitly not positive, I never experienced any symptoms, and they relented and let me recover the procedure some number of weeks later – with no change in testing.
edit: I neither made nor recanted any claims as to the positivity of the other 48 in my first comment, I do not know why you are asserting I edited claims out.