Thanks to Joe for pointing this out. Heather Simmons, the driver who hit Diane Whitman from behind on Olney-Latonsville Road/Route 108, killing her, was found guilty of Negligent driving and "Not Keeping 3 Feet" and charged $400 in fines. That may be the first prosecution of the 3 feet rule in the region.
There doesn't seem to be any sign of points or loss of license. There may be a civil case that follows, but still it looks like 2 tickets for $400 is the extent of the punishment.