Radgirl, I'm afraid I'm not familiar with the WHO checklist but having done a quick Google it makes a lot of sense..
Kind of like when the surgeon came round to have a chat to my (then) partner about the op she was about to undergo. And explained that they wanted to make damned sure they had got it absolutely right (and didn't remove the wrong kidney or bit or whatever) so there was a cross check in the operating theatre so they looked for the 'big blue cross'. And he then got out a marker pen and drew a large blue cross. On one of her boobs! And he agreed with her that that was indeed the problem area (and the correct boob) which needed to be operated on.
Momentarily embarrassing, yes. Lifetime of anguish and unecessary lawsuits - avoided!!