There are probably a lot of other facilities where if you look hard enough, you can catch a glimpse at some point in your race.
There sure are, especially when you are swimming on your back. That guy we saw swim the 1500SCM backstroke last weekend could have known (and probably did know) his splits for every 50. I bet he picked it up after 1000 because he saw that 1000 split and said, "hey, I can go under 21:00 if I just kick a little harder." (And in fact he did, approximately tying the time I swam on my front.)
Are there any rules that prohibit your counter in the 500/1000/1650 from doing board movements to let you know where you are in your pace strategy?
No rule exists about moving the lap counting cards.
That said, I believe that using the lap counter for displaying splits is a clear violation of both the spirit and letter of the rules regarding use of a pacing device. The swimmer should be disqualified.
