Bankers Box Ban?

It sounds crazy, but my two most recent visits to Fedex shipping centers have left me with the impression that a ban on bankers boxes may be imposed. First, a Fedex agent insisted on repacking documents from my bankers box in Fedex boxes, and warned these boxes would no longer be accepted. Tonight at the same location I was told that they are starting to enforce a rule against boxes with openings on the side that function as handles. She accepted the box anyway but I wonder what will happen the next time I need to hustle something over at the last minute. Fedex’s packing guidelines, https://www.fedex.com/downloads/shared/packagingtips/howtopack.pdf , specify that bankers boxes can’t weight more than 30 pounds and that the box should be secured with 2 inch packing tape placed on in a tic-tac-toe pattern. However it doesn’t appear to restrict the use of bankers boxes with grip gals, something nearly all have.