Syncing prefetch files

XP Pro, SP3, current updates, Lenovo T60p at 2 bg
I've been into computers since 1979, but much of what I once knew is long gone.

I use a program to synchronize files on a full clone, external extension backup drive. Upon running the analysis preparatory to the actual synchronizing it posts notes about various files. These posts invariably include warning notes about all prefetch related files, saying that I should take a look at them before proceeding. It offers various options including ignoring the files, ignoring the warnings, etc., but looking at them is meaningless to me.

Is there some reason, unrelated to any specific sync program, why .pf files should _not_ be put on the backup drive in my attempt to make it identical to the primary system drive?

(There is a very good reason I don't just make a new clone.)