Several answers on this site (e.g. 76305) suggest that HTTPS 30x redirects to HTTP aren't a great idea but that the pattern is widespread.
Looking at the choices that the Chrome team have made, it's clear that they consider their role to be proactive in security. It is foreseeable that browsers might start to deprecate, warn or even prevent HTTPS URLs redirecting to HTTP ones.
Is there any evidence of this blocking happening? If so any indications about the likelihood or timeframe?