Maybe this is a change planned for use in the new guild system? If it was coming soon I'd say it's smart, as obviously towers would be busier again and the chance of you killing the same person again and again without killing anyone else would be extremely low, and this would also discourage players looking to reap rewards from getting their pks all against the same person(s) in a cave with bushes somewhere.
**im assuming that there will be some sort of new pk system in the ngs with some sort of rewards**
This is actually a good little change, but should have happened years ago when people like raeven were making the most of killing the same person over and over again hundreds if not thousands of times with a bush. Now it's just a hindrance for people in quiet towers