This has happened to me a couple of times now, so I thought I'd see if anyone can give me an answer.
Last night I took off from Philly Intl for a VFR flight. However, once the tower handed me off, the only ATC option I had was to file an IFR flight plan. Conditions were fine for visual flight (few clouds at FL200, visibility +20 mi), but I did not have any options to contact ATC or contact another airport. I finally just pulled up an old IFR plan (not moving my aircraft to the departure location), then cancelled IFR after the readback and everything was fine.
My question is: why would the Philly tower clear me for a VFR flight and then not let me contact anyone once I was up there unless I filed IFR?