>>>Violating this statute does not
>>>incur jail time, but there is a fine and you will get a nasty, nasty
>>>note from the Bureau of Standards.
>>
>>And if this rule is violated and something gets hurt, triple damages?
>
>I'm having a hard time envisioning a situation in which the use of a
>slotted screw instead of a Philips or Torx one would actually result
>in an injury...

The entire reason the Robertson screwdriver<1> was invented was because a screwdriver salesman, (named Robertson), had a flat-head screwdriver slip on him and seriously injure his hand. Although, it wouldn't surprise me to see a similar injury from a Philips spiralling out of a stuck screw<2>.

<1> What everyone should be using rather than Philips, except that Robertson wouldn't agree to let Ford licence production rights.

<2> Generally the less bad thing that happens when a Philips screw gets stuck. The more bad being that it destroys the head in a way that you can no longer get a grip on it.