A healthy specimen, especially one that is already acclimated to tank life, will ship fine. Of course, a lot depends upon how well the shipper handles and packages the anemone.
When I've shipped, I've included about 1/2 bag full of water, triple bagged, and used 1 or 2 heat packs (depending upon the time of year). They've all survived the trip fine, although some have been in pretty cold water when they arrived (heat pack failure).
FWIW,
Kevin