Some do, but if you hire a union busting law firm the first thing they have you do is read a statement alleging impropriety with the union cards, in order to initiate the NLRB process.

Companies aren't required to present any evidence other than "we have reason to believe" so it's pretty much a ritual at this point.

Yes, but it's uncommon enough that doing so is called "voluntary recognition" of the union, acknowledging that the expected process is to file the cards and then do the NLRB election.