What time is it? Watches and horology

Do what a friend of mine does and ask nicely if the seller will mark it as a 'warranty return' (if a new watch - more effective than 'gift') and of a low value. Say around $40. Allegedly 9 out of 10 sellers don't have a problem and tax / handling fees can be circumnavigated.

Are there any issues with the insurance value of the package if it is an expensive watch? i.e. mark the value low to dodge import taxes, but be unable to insure for an appropriate value?