Originally Posted by
aacharya
International airports do not have the same rules/concerns about overnight baggage as the US does. Not sure why you cited a UA rule for a connection on LH (where their rules would apply).
Check-in was occurring with UA, so UA's rules applied.
LuxFlyer stated recently that there is a set of airports where the 12-hour rule does not necessarily apply, but that feels like it should be at the traveler's discretion. Many people will want access to their checked luggage when there's an overnight transfer, and that's not the least bit suspicious or indicative of someone trying to do hidden-city ticketing.