Board Thread:Naruto Discussions/@comment-9782468-20151224201414/@comment-734582-20151227125257

JouXIII wrote: Well, they ARE shinobi, and(like you said) in wartime as well. I'm pretty sure they are aware of their possible deaths and there were some kind of preparations... As far as customs go, graves are reserved only for man/wife situations. Even family is rarely placed next to eachother. in the vicinity, sure, but actually smack dab next to eachother is rare.

It's possible Rin died close enough in time after Obito to be buried next to each other, but otherwise it seems doubtful preparations were made. Especially since Obito was not Rin's boyfriend -he had a crush on her but not vice versa.