You really don't want to die because your boots were too loose
I almost always have teva sandals strapped to my pack because I like to blue line a lot of stretches...
But I have also always been of the opinion that wet feet are better than a wet ass! If you're going to try to rock hop in the hopes of keeping your feet dry you should invest in waterproof boots and find a shallow ford. and if you're crossing deeper glacial run-off you should be prepared to take your time crossing (even if it means waiting for better weather. You really don't want to die because your boots were too loose