In reply to Chris.

I don't see any advantage to it. Let's say that your sample is size N and there is 1 event, so the observed sample statistic is 1/N. Then the bootstrap distribution if the sample proportion is going to be a discrete distribution with values at 0, 1/N, 2/N, 3/N, 4/N, and possibly 5/N. Not many samples will have 3 or more events, so most of the probability is for 0, 1/N, and 2/N. The percentile CI will probably tell you that the CI is [0, 2/N] or [0, 3/N], and I suspect the BCa will be similar. You can run an example where N=1000 to see the actual numbers.

The issue isn't really Percentile CI vs BCa. The issue is that for a rare proportion, the bootstrap distribution is discrete because the statistic can only take on a small number of possible values.