This avoidance manouver leads to the Andrea Doria syndrome...
In the rules for power boats, there is an explicit instruction to this effect:
(c) A power-driven vessel which takes action in a crossing situation in accordance with subparagraph (a)(ii) of this Rule to avoid collision with another power-driven vessel shall, if the circumstances of the case admit, not alter course to port for a vessel on her own port side. "
While the rule-writers didn't add the same caveat to the sailboat rules, its the same circumstance...the standon vessel should not turn towards the give-way vessel, or they may end up hunting each other, letting someone duplicate the Andrea Doria.
That is the whole problem; without eye contact, do you know what the other person will do? If I have eye contact with the helmsman, I have fair confidence that he may come very close but that he sees me. Waving is good. I sail the Chesapeake, and many come quite close.
On the other hand, I had an episode last year that was too close. I was full-and-by at about 9+ knots on starboard (light catamaran) and a large (60') well-trimmed mono was doing the same speed on port. We were closing very fast and the bearing had not changed in several minutes. As we got close (10 of my lengths but only about 20 seconds), he apeared to bear-off, but it was only a wind shift. Just as we got into the critical zone, the wind shifted back so that he would cross somewhere behind my mast. I had zero eye contact, because the boat had a large sweaper. If I tacked away, I would loose right of way and stearage and would probably be hit on the transom (and his boat would cut mine in half). If I bore off, we would close at 20 knots and I would have to PRAY he did not see me and also bear off. The Andria Doria case. Crap.
I bore-off hard, passed him very close at nearly 25 knots combined (quick acceleration on a reach), and scared his useless girlfriend so much she fell off her seat (she was facing aft). The skipper jumped all over the place, startled because he NEVER saw me. I loudly suggested that if he couln't keep a bow watch he should stay at the dock.
Since my boat weighed 1200 pounds to his 50,000 pounds, and given the speed, someone would have been hurt or worse. I would have sunk in moments.
It is all about eye contact. If you can see each other, it can be safe very close. Without eye contact with the skipper or and ACTIVE crew member, you can only give wide bearth and hope there are not too many other boats around to crowd things.
Though bearing off was the only choise I had at the last moment, it was wrong in a number of important ways and it scared the hell out of me. I should have realized the boat was without a watch and would not react predictably.