All of my nasty screwdriver problems have been with flatheads and cheap heatsinks.
I use only magnetized screwdrivers. If it's normal, I use a stout fridge magnet (the effect will usually last a few weeks).
The WORST I've ever done was I swiped it (accidentally) over the BIOS of my AK35GT2 once, and when it came back up, it gave the same error as when it is first booted or when the BIOS has been flashed (wrong CMOS checksum somethingrather). Go in, save, all was fine, and the board is still in use.
I personally would think all the screws dropping and screwdrivers slipping with normal ones would cause far more damage (definitely more irritation!) than having a magnetic screwdriver.