/Y-M-M-V/
[from the standard disclaimer attached to EPA mileage ratings by American car manufacturers]
cav.
- A ritual warning often found in UNIX freeware distributions. Translates roughly as "Hey, I tried to write this portably, but who *knows* what'll happen on your system?"
A qualifier more generally attached to advice.
"I find that sending flowers works well, but your mileage may vary."