Got a problem? Make threats of prison at it. There you go, problem solved even if we haven't entirely defined what the problem is or what a breach of the law related to it might really constitute. Just follow the lead of those arch-prison enthusiasts, the Securities and Futures Commission, and bang them all into jail.

Yes, it's true that developers have a way of overstating the floor area of the flats they sell. They like to include each flat's share of every conceivable common area in the building. And, yes, it would be a good idea to establish standard floor area definitions to which all sales brochures for new buildings must conform. In fact, we've been too long about doing it. We should have done it years ago.

But if developers and their employees are to be thrown in jail for pledging more than they deliver, what about doing the same to legislators? Sauce for the goose is sauce for the gander, they say. Why not throw legislators in jail for making promises they do not keep?

I'll tell you why. It's because the entire Legislative Council would then be in jail, bar those functional constituency members who represent commercial sectors and promise only to deliver government contracts to their constituents. These are about the only promises kept in Legco.

We could also throw three quarters of the advertising industry in jail. Take fashion promotions, for instance, starring all those teenage girls who make themselves look older by pretending to be starved, drug-addicted rape victims. The adverts hold this out as a promise of the good life if you buy the clothes they push. Someone ought to go to jail for it. In fact, you could jail almost anyone who works in any sales and promotions effort in any industry if you believe that failure to tell the complete truth in sales pitches should be punished with a prison sentence.

Salespeople work by spinning a little magic around your head. If it's not potatoes or an electrical connection that you are buying then you mostly are charmed into buying it. Sales time is time to bring on the magicians with the smoke and mirrors. It has never been otherwise.

That's why commercial law still operates on the principle of caveat emptor, let the buyer beware. Politicians around the world would like to replace it with 'caveat vendor', let the seller beware, but all this does is spawn legions of regulators who write massive rule books that no-one can ever hope to read or understand. It doesn't work. Caveat emptor may be rough justice but it works. You are responsible for your own life.

Our legislators, however, have more than just statements about floor area in mind when telling developers (and their employees, remember) to beware or go to jail. They are still upset at how Henderson Land Development tried to whip up enthusiasm for a Mid-Levels block by pretending to have achieved record-breaking prices for flats already sold there.

Naughty, naughty, naughty, but did anyone in authority at Henderson Land, as a condition of sale, sign a sworn statement to other buyers that such sales had actually taken place? If so, then take it to the cops as an open and shut case of fraud. If not, well, chalk it up to experience and don't be so stupid as to swallow a tall sales story next time.

I'd be very surprised if any genuine Hong Kong buyers were among those fooled. I think the buyers who paid too much were all trying to clean up dirty money taken out of the mainland. What a laugh that Henderson cleaned them out in turn.

It can't happen again if legislators get their way, however. It will be the Henderson people who go to jail then, not the dirty money boys.

But the worst of such legislation is that anyone who works for a developer can risk seven years' jail for wrongly guessing what meaning is put on the word 'misleading' by legislators who have no experience of property development or the sales context in which homes are sold. That's just plain unfair.