Well, it seems that in Japan girls going out with girls is a phase. And girls who don't stop skinshipping or "playing around" are considered childish, and the parents might intervene. So I don't think yuri-teasing causes much, well, anger and disappointment among the majority of Japanese fans. It isn't taken seriously and the yuri fanservice doesn't help either.
The best scenario for me in this case is an open ending with/without implied het relationships later on when they grew up, that's my lowest expectation for KumiRei. I'm sure even if there's a slightest chance they're canon, there won't be any tied up for them in the anime anyway. If it's not outright labeled as yuri, then there's no guarantee of lesbian relationships. Either go het, an OE or best friends for life. Heck, there's no guarantee even for the yuri labeled shows.
I can never feel safe with yuri-seemingly-anime in which guys exist as potential boyfriends. I still hope we get more real girlxgirl relationships than teasing and friend forever. For now, good bye Hibike.