After a lawsuit against a bicycle manufacturer for "unsafe design," all cycle manufacturers began installing small "swells" at the bottom of front fork axle slots. The intention of these swells was to prevent an untightened quick-release wheel from falling freely from the fork.

Although universally hated by experienced cyclists, the "lawyers lips" (as the swells have been called) are now standard on all bicycles at all price ranges. Experienced cyclists hate these swells (and often file them off) because they delay the removal of the front wheel. With the lips in place, a cyclist must not only release the quick-release cam on the axle, but also unscrew the axle nut by many turns before the front axle will spread enough to drop out of the front fork.

Hope this answered your question.