Yes, they do this for sure. I ground the magnet box right off and filled it with styrene card, but I run my car on wood (no magnets).
Like so:
You can go crazy with the mods on these. I run a Pioneer motor, Slot.It axles, guide, bushings, and gears, and SCC wheels. Not much Monogram left in it except for the body, interior, and chassis (each of which has been modified somehow). My car runs really well now but not cheap by any means. This is what it looks like now:
So low that I can't fit the exhausts between the body and the track any more!