[paulk]

To answer your original question... things have changed. Forget what you thought was the case "many years ago". Your sails could be luffing while you are on port or starboard tack - with the attendant implications. Your sails do not have to be filled for you to be on one tack or the other. Look at the definition of being on a tack- it's your windward side, regardless of how your sails are trimmed. If you are tacking, you have to keep clear of other boats, but that's not because your sails are luffing, it's because you're tacking.