[Arran]

 There was no relation between Warwick and Philco at all that I am aware of, Warwick was a manufacturer of private label radios mostly for Sears. I have seen rosette style knobs on some Airline brand radios as well, which may have been made by Belmont. If there was any relation at all it was to whatever plastics molding company made the knobs, most radio manufacturers either contracted out the job of molding plastic parts to outside firms, or used generic off the shelf parts, Philco was no exception.
 As for hotel radios all of the ones I have seen had a timer and a coin slot, I could imagine the nightmare of hotel management trying to keep track of keyed knobs for their radios, the replacement of such things would easily outweigh the earnings from whatever fees they could charge for using the radio. Also most of the hotel radios one sees are from the 1940s and 50s, typically with an AA5 or AA6 chassis inside, I've never seen even a photo of one that was older.
Regards
Arran