/var/mail question

[quadrant]

I was temporarilly using pine to retrieve my email, and upon exiting the
program, pine notified me that the /var/mail directory was
vulnerable, and advised a chmod 1777 of such. The default is 775.
What are the implications of this, and won't 1777 make the folder more
vulnerable? My understanding was that if the SUID bit is turned
on for either U, G or O, that security is more at risk. Please
let me know what I should do...
Thanks,
Eric