Looking back, the only place above that I mentioned "obligated to tack" was in reference to taking too much room to tack due to issues on the boat. Without calling up the reference at the time, my point in that post was to point out the principles of room and seamanlike actions, as expressed in Case 103.
I will agree that "obligated to tack" doesn't appear in the rules, but stick to the interpretation that mark room does not give a boat ROW, and is limited per the definitions.
