I suspect that the coin validation services will offer an API which will evaluate a compiled spend (collection of inputs) and produce a valuation. Anyone will be able to use it for free and a wallet extension will do the grunt work.
Sure, CV racketeers will assess the taint for free, and charge you for the process. You're painting a fairly benevolent picture of what is actually a fairly trollish, abusive concept.
In this day-n-age it is quite inexpensive to do a great amount of processing, particularly if one can leverage the principles of economies of scale. I suspect that taint analysis will be able to do this quite effectively.
What is more difficult to come by is good individualize intelligence data. That is why we see very valuable and useful services 'given away for free' by entities who run football field sized datacenters. There is no 'free lunch' in this world and everyone knows that intuatively but it is relatively easy to ignore.
I don't doubt for a minute that many parties would be delighted to off-load the burdon of running the Bitcoin economy and do it for 'free'. Nor do I doubt that a certain number of them could do it with ease even if if the block chain size were effectively unlimited.
I will be using coin validation if doing otherwise results in a significant loss or loss of utility of the coins in my wallet. Probably you will as well when the rubber actually hits the road.
If you do that, you stand to lose both value and utility.
Not before I have made some bucks out of the deal. This is
exactly the same principle that drives '
the tragedy of the commons'. In short, it works. Doubt it if you dare.
Tell me something, what's the big argument against instituting the taint/validate scheme in the incumbent monetary system? The same risks apply, so why are we not consulting a list of tainted monetary units before we accept it, right now? There's nothing practical stopping that system from being developed (just assign all coins and digital transfers an identifier, like with paper bills and cryptocurrency). If anything, it could work better, being a closed system.
Political resistance and options. I don't doubt that there are many who would like to do just that, and I suspect that there are schemes in the works to attempt it. The trouble is that it is a somewhat thorny problem in that the harder one pushes, the stiffer the resistance. And the resistance could spill over into other areas. If it is ever attempted it would have to be during troubled times when the infrastructure to enforce it has a chance.
To be a little bit more positive vis-a-vis Bitcoin: I suspect that my ideas for how to destroy Bitcoin would actually be highly effective. But destroying Bitcoin at this juncture (and maybe forever) could very well be highly counterproductive if it is replaced by a stronger system which is very likely. Thus, destroying Bitcoin might not be attempted. If I put my 'evil strategist' hat on, my strategy would actually be to leave Bitcoin alone or even prop it up and try to damage the competition.