Open it up, dammit!
Air Drop is nice and all, but Apple (like so many others, incl. Google re new Jabber-incompatible Hangouts) has to accept that vertical development, with all its benefits, ends when it comes to networks, i.e. when people and devices communicate with each other we need standards every one may comply to. Open and free standards are cool of course, but even if a company has designed a proprietary protocol they should license or publicize it so others can implement it on different platforms.
Jobs promised this for Face Time the instance he announced it
and never delivered. One of my greatest disappointments with Apple so far. (i)Message is another case, iCloud too (since it employs standard protocols underneath, just obfuscates them) and Air Play etc.
If they must, they could keep it Apple-only for one SW/HW generation to make it a buying incentive, but release it to third parties after that. Its really sad to have to wait for some hacker to figure out some scrambling key and reverse engineer the whole thing, as has happened for Air Tunes/Play for instance.