"Reset" Script, Anyone?

[beno]

Hi;
I am half a world away from my console. If I make a mistake entering my 
PF rules, I could lock myself out. It would be nice if I had a script I 
could activate by cron that automatically flushed out my rc.conf that 
I'm experimenting with and loaded the original. That way, I could set 
the cron, load my experimental rc.conf, reboot and see if I could still 
connect to my box. If I couldn't, then all I'd have to do is wait a few 
minutes and then I could try again. Surely I'm not the first person to 
have thought of this. Anyone have a script that does this?
TIA,
beno