So far there have been no leaked drops. It will be really easy to tell if/when it happens because it will dry into a trail of borax which will appear as a white powder on the cups. Given that  I've obviously gone for function over form I think it's a pretty reasonable precaution to take. I put the side of the case on when I have visitors around so it's hidden from view. The alternative was to reposition the case on its side and upside down (eg rotated 90 degrees anticlockwise) so that the drops would fall downwards away from the boards but this makes accessing and checking on things very difficult.

When I first setup the 5970 with watercooling I had a glycol coolant loop that leaked onto the bottom of the case (there was no 5750 at the time) and some of it dried into a horrible green mass of glycol coolant. That turned out to be an epic fail because a lot of microorganisms thrive on glycol as it turns out, so I decided to use borax as an experimental alternative. So far I am happy with it. In the future all of my work with watercooling will most likely be done with silicone-type tubing (think medical tubing) because it forms a far superior fit on any connectors that are used and has a much lower risk of leaking. The chemical stability of silicones versus PVC is also another advantage.