I think the jury is still out on the ideal shipping method.
I've had probably a dozen or so anemones shipped to me in various ways -- large bags with lots of water and air, small bags with lots of water and not much air, as well as almost no water. And I've also transported anemones from friend's houses and LFS in many ways -- in a bucket, a cooler, in a bag with no water, in a bag with lots of water, etc. My point is that of the six anemones that I currently own (4 gigs and 2 mags) there were so many variables involved in how the nem traveled that it's hard to tell which is the best, and the reality is that the mode of transportation should be treated on a case-by-case basis.
I witnessed one anemone completely invert its stomach during the 45 minute trip home from the LFS. I eventually died even with antibiotic treatment. I recently received a gig from an online dealer and it didn't need treatment at all -- it arrived in a bag so small that the nem was folded inside, and the bag had barely any air. But even in the QT tank, it never deflated.
A few more comments:
1. The way anemones are shipped should be species specific. As previously mentioned, gigs seem to ship better without any water. We can also assume that those nems that are exposed to air in the wild should ship fine without water, so this would include magnifica. Other nems, such as BTAs, are hardier anemones, so shipping methods may not matter.
2. It's more important that the nem is healthy when shipped than to include medication in the bag. I don't think one day's worth of medication will alleviate shipping stress, nor will it prevent an anemone from getting sicker. I believe that when an anemone expels zooxanthellae, it's this dead zoox that must be removed in order to prevent reinfection. If it's allowed to sit in a bag with dead zoox, the nem won't get better.
3. The condition of the nem plays a large part in how well it does in shipping. For example, they should not be fed prior to shipping as they may expel any partially eaten food during shipping, which will of course foul the water (if water is used). Partially or even fully bleached nems appear to ship better because they don't have dead zoox to hold during shipping, not do they have any to expel.
The only way we'll know we'll be able to gather even the slightest bit of information on what the best way to ship anemones is is to conduct an experiment where healthy anemones are shipped to various locations. However, only someone who's completely twisted will attempt such a thing with their healthy nems.