For me it has to be like any other type of business - it's all about due diligence and earned trust.
As previous post's mentioned the similarity with property:
- would you give £10k to lease a workshop off a guy you met in a pub without getting your lawyers involved?
- you would still get the same lawyers involved if you are a supermarket brand leasing a superstore premises off a pension fund...
As the industry matures and more money gets involved, the legals will evolve too.
For all of the nominet members here - has it ever been suggested that some type of system evolves similar to the Land Registry... you might think you own your house, but if it's mortgaged and you stop paying, the bank exercise their charge over your ownership. In the same way a Lessee could have a charge placed on a domain that stays in place until a contract ends or is breached - and to be workable, as already suggested it would require some system of domain escrow.
I guess the biggest difference between land and domains - for the purpose of this discussion at least - is that 'they' cant make any more land so leasing is the only way to get to use land that people dont want to sell - but 'they' can make / enable more TLDs - so maybe the need to lease only lasts as long as it takes the market to move beyond the fashion for .com / .co.uk
