Do you think that generating a new identifier every day would do the trick?
No, I don't think so. It would break correlation in time, but it would still enable correlation in space, as in "these two locators lead to the same location". That may or may not be a problem for *site* multihoming, but it definitely is a problem for *host* multihoming, e.g. a host with a WiFi and a GPRS connection.
Some might consider it a solution, not a problem. For example I can imagine it helping to meet "911" requirements (an emergency VoIP call arrives via WiFi, but back-tracking to GPRS gives better automatic geolocation).