I drilled mine out, and replaced it with tiny nuts and bolds.

Drill out, re-rivet.

I use a dremel w/ a cut-off wheel to remove the rivets, grinding off the flared end of the rivet., Once the flared end of the rivet is ground off, I drive the rivet out, using a small punch and hammer. I also keep a damp rag nearby to cool the rivets as I grind them off...especially if you plan on re-using the plastics. The rivets get hot when you grind them, so cool them off w/ the wet rag so you don't melt the plastics. This is really important if you're removing ramp flap...you don't want to melt the ramp.

The problem I see with drilling the rivets out is, sometimes, the drill bit will bite into the rivets, causing them to spin which, in turn, mars/melts the playfield plastics.

For plastic like signs, i use a very sharp drill bit by hand to cut away the flared side. After removing most of the flared part I carefully punch out the rivet as mentioned above. The rivets are brass so they are pretty easy to cut with the sharp drill bit by hand. Sometimes the tube part of the rivet will just fall out. Takes maybe 5 minutes and minimal risk to damaging or burning the plastic. I do the same on plastic ramps when replacing spring steel ramp flaps.