Completely separate issue IMHO. A US Citizen or LPR doing a MR should be no big deal because he or she is simply returning to the home country rather suddenly after departing. But the inspecting CBP officer cannot prevent the pax from returning home assuming that there are no irregularities.

However, a foreign national seeking to enter the USA under the Visa Waiver Program is completely and utterly at the mercy of the inspecting CBP officer at the port of entry. If the officer decides that the story is just too peculiar (like some young guy who is terrified of making a mistake, and happens upon a MRer) and decides that the pax is inadmissible, then the pax is SOL.


Furthermore, the I94-W form says that the pax cannot appeal or contest the officer's decision:

WAIVER OF RIGHTS: I hereby waive any rights to review or appeal of a U.S. Customs and Border Protection officer's determination as to my admissibility, or to contest, other than on the basis of an application for asylum, any action in deportation.