Why is there a punctuation "rule" ?

I noticed in the log I am giving out 501 errors with:

"Malformed envelope from address: Invalid punctuation characters"

This appears to be legit mail for my users from things like a Microsoft 
mailing list:

<10_302356_odpHB3m/[email protected]>

In this case the forward slash seems to be the problem, I have others with 
an = sign in it.

1) What is the reason behind this "rule" in relaydelay.pl ?
2) How can I accept this mail (assume I can't get the sender to remove the 
punctuation characters) ?
   a) If I whitelist the sending IP will it bypass this check?
   b) Can I comment out this check or remove the = and / from it?

Thanks!
Dennis