Shipping Basses

In a conversation the other day with some band mates about shipping basses
(or those little 6 string instruments self indulged people tend to prefer),
we had something of a difference of opinion as to whether or not it is a
good idea to relieve some of the tension on the neck (via loosening the
strings) before shipping.

So for those of you that may have worked in music stores, or have received
instruments directly from manufactures, what is the general consensus on
this among manufactures when shipping? Do they typically send them out
tuned to pitch, or with the strings loosened?

For that matter, what about you guys that fly with your basses on a regular