If you are the person that bought the transistor (and then later sold the tube), when you get audited they are going to be asking where the money came from that you bought the transistor with. If the other guy gets audited and they see that someone bought a transistor for tens of thousands of times the reasonable market price, they are likely to take steps that result in auditors knocking on your door.Not my problem where the money came from.
Do yo worry about where other peoples money comes from when they buy something from you or if they get audited that their auditor is going to track you down and question you about what you sold and why?
I never have.
Now, the claim that you are simply a really bad business person and are eccentric and thought it would be cool to have a $25k transistor and that it might have investment value might fly to some degree. But when you bought it with money that appeared out of thin air -- well, that is probably not going to fly (since the whole point of laundering money is that having money appear out of thin air doesn't fly very well).
If something turns up in the audit (done as part of an investigation, particularly a federal criminal investigation) of someone that you've done business with, then the investigators are very likely to track you down and question your side of the transaction. If you can't satisfy them that you are on the up and up, then they can expand their investigation to include you. Happens all the time. Even if the audit was not in conjunction with a criminal probe they are likely to bring the matter to the attention of the FBI, the IRS, and whatever other agencies they think might be appropriate.
