I believe one way to help slow down the keg theft problem is for existing home craft brewers to promote the many advantages of buying a well designed vessel, or set of vessels to any newly interested person of the hobby in the first place.
When all the keg conversion fever first started the choices available to hobbyist were limited and usually very expensive. Now however there's great choices available of well designed purpose built vessels to suit any budget, in most cases they're lighter and easier to handle, carry, clean, and store. Any do it yourself project like keg conversion for a beginning brewer always........ always ........ always, involves numerous trips to the hardware store and a generous investment of money in tools, drill bits, cutting discs ,lubricating oils, gloves, safety goggles ....... yada yada yada! This also eats up lots of a persons time and energy flitting from store to store getting everything you need. It can be an enjoyable pastime to some of course but the point is its probably better to do a few hours overtime at what your good at and just buy what you need. If you buy entry level vessels and look after them you'll always sell them easily if you ever want to upgrade to better ones later.
I know if I were starting out again the purpose built choices available now would seal the deal for me. It's also a great way to substantially support your chosen Home Brew Shop or On-line Supplier and maybe help keep them in business for the future to offer even more great gadgets as they become available :beer: