I believe anyone who has ever spent a significant amount of time buying domains from different registrars at one time or another may be likely to run into this problem.
*For The Record I would like to clearly state that I feel that the practice known as domain tasting is wrong *
My personal 1st hand experience is as follows:
I used always buy my domains from a particular registrar that was associated with web hosting. A friend then told me about a different registrar, and it provided both better prices and more useful tools such as a bulk domain search feature.
So I started using them, the one day, I saw the domain I wanted was available via ( a special robot that provides statistics on domains ) yet there was neither a "This Domain For Sale" notice, nor and other clues as to why I could not get:
That particular domain, with that specific TLD (most likely a .com possibly a .org)...
So I zipped over to some other registrar, (I try to limit myself to three of four so I don't go crazy tracking down my domains) and quietly registered that domain, and vowed that if this were to happen again, I would the same thing.
Therefore is there was some shady practice or some "corrupt" sort of game going on, I would readily have the remedy at hand to resolve it, instantly and without a fuss.
As an US citizen, or simply as an intelligent citizen of the world, it should be no surprise that there in anything endeavor where one may stand to profit, there will be a tendency for people or businesses to try to "cheat" the system or otherwise try to tweak things to their advantage.
Particularly with domains, people who are trying to invest and develop valuable portfolios should use the fact that they are a "larger than normal buyer" and do the best that they can to make it work to their advantage.
Like anything else in life, one needs to learn from the mistakes, and not let others take advantage of them.
Additionally one should not "get to crazy about such things". Finally one should realize that domains do have specific expiration dates, and grace periods after expiration. Sometimes the domain you want may show as "available" because it actual expiration date has gone by, however the registrar of record might have standard procedures allowing their registrant to renew the domain within a set number of days, possibly between 2-4 weeks!
On a related note, the real issue goes far deeper than this particular practice in this particular industry. I try to write about such "corrupt" practices when I learn of them as a first step, to pushing those bodies who regulate such things to crack down on such practices.