Of course I encourage people to sex their animal upon arrival this way if a mistake is made it can be corrected immediately, however as Ed said, sex won't change whether it is 6 month or 2 years down the road and therefore the mistake should be corrected regardless of the time frame that went by.
For those that think after 2 years it's unreasonable to expect compensation, if hets don't prove after 2 or 3 years YOU or anyone would expect compensation right? Well sex is the same thing.
Yea Deborah, but how would you know it's the same snake? That would be my only concern.