Yeah... and there's anecdotal evidence that oocysts will settle out in still water - apparently they are denser than water. So maybe one could greatly reduce the number of oocysts ingested in emergency situations simply by letting water sit for a few hours and then carefully decanting off the upper region of water?

You wouldn't happen to have some lying around the lab that you could confirm my theory with, would you, Pete? Giardia or Crypto or both?

As we've discussed previously, it requires a certain quantity of ingested oocysts to cause problems - a few / several won't bother most folks at all. And some folks seem to be unaffected by fairly large numbers - huge variability in folks vulnerability...