> How are trap streets “the trick” if they are not copyrightable or enforceable under US law?US law is not the only law.
Current US law has not been as it is for the entire existence of the US.
Trap streets and other such devices have existed much longer than the US.
As well as copyright law the trick can help detect beaches in contractual agreements that cover use of information from services. Action based on such breaches do not necessarily end up in a court of law at all.
Out of court settlements do not necessarily rely on the letter (nor intent) of the law, but often instead the expense (money directly, time, potential reputational risk) of defending a position even if the law is on your side. The threat of action is often enough to make the other party cave and such actions will usually happen well out of public view (I know of one instance involving a list of phone numbers, that I won't go into in detail because while there is no NDA or such in force this discussion is not worth irritating people I have the confidence of!).
> clumsy attempt to work around this.
That the trick is clumsy does not mean it isn't still commonly used (it absolutely is) or that it has not been used in successful cases between map makers and such (it has, one significant example is given in the paragraph directly following the one you selected to quote from the page linked in my previous post).