If the seller is accustom to mailing saddles, I would let them do it. They usually get better rates on shipping too.
Why are you planning on buying a saddle out there instead of close by?
There's just not a lot to choose from out here western-wise. I've looked on the Seattle craigslist and found a lot of really nice saddles among other things. I don't think a lot of these people would be accustomed to shipping, but I can ask. =)
I just assumed you meant new - sorry. You can take it to a UPS store and let them package it. Doing that, you can avoid UPS claiming your packaging was faulty if there is a damage in shipping (happened to my son when he bought a set of speakers from someone in TX)
I think alot of it is luck as well, I have had airlines damage luggage that had nothing but clothing in them,
A tough saddle should be able to take alot, if it was on a horse flipping over and bronc riding, a good tree should withstand a good packed trip in a suitcase/ large box under the 50 lbs, 62 inch total LWH
Always a chance, no doubt, even with shipping UPS or USPS.