I would actually say this is true for most of the gods, but also Odin in particular. I do not accept messages from anyone claiming to speak for Him unless they present some very specific criteria AND can continue previous conversations I’ve had w/ Him (most of which are never on public display). As a seidhrkona who gets LOTS of the “what does Odin want from me?” types of questions, even if I manage to get a message for them I always encourage the person to go directly to Him, first and foremost. If the action wanted is a big one (such as marriage or even patronage) there is always LOTS of corroborating evidence (dreams, signs, omens, messages from other people, etc)--so much so that there really should not be much room for doubt.
In our long-ago Heathen past, seidhr was generally reserved for emergency situations (maybe because people were too frightened of seidhr folk to approach them otherwise) in which people had tried other means of obtaining answers on their situation, or were just so overwrought that their usual methods of getting answers were not working and they needed some outside help. What see a lot of now though is people becoming dependent on seidhr answers, the way people in other traditions become dependent on Tarot readers or astrologers. I do not ever want to be that person who comes between you and your god, so I cannot stress this enough: ask for an oracle if you feel you must, but not as a substitute for going directly to them, in some manner. Almost everyone has SOME tools they can use for doing this, but for those who feel they need a few pointers I am going to be posting a suggested reading list in January.