I'm not a big fan of online buying boardgames (live is like a box of chocolats, you never know what you gonna get..., and then in the rare case you managed to find a mint copy, the mailman damages the box)
I purchase all my games from online stores, and I have never had any issue. They always arrived in mint conditions.
Usually the game box comes inside a bigger package, with pieces of paper (or other stuff) surrounding the game box, in order to avoid damage with the transportation.
Some online stores are more careful than others with the packing, but still maybe I've been very lucky.
Besides, I'm not sure if it helps, most stores uses couriers instead of the regular postal services. Maybe they are a little more careful...