Some time ago I made a little application where I can send instructions as a Flash animation file. Only thing is that there is no animations, simple plain text.

The trick is that the program won't show the text (instructions) if the computer clock does not show = or > a certain time and date.
Once I had somebody changing their PC's time so she could fool the computer and make it think it's time to see the instructions already.

What she didn't know is that the time was not picked up from her local PC, but from the atomic clock on Windows.com and that the instructions were instntly deleted.

Needless to say she never could read them, and finally had to admit to her "not knowing" the instructions and her "crime"...

Never happened again; it works wonders on a sub's patience.