Personally I compare it with the standards for Casual observations. If they provide no media evidence, even if they give a great description, it can never be RG. Someone gives a detailed description of a crow (enough to rule out grackles, starlings, ravens etc.) and says that it went “caw”? Still not enough if there isn’t photo or audio. Why would that standard change if they do provide media but it’s no help for ID? (I don’t actively go around knocking back crow observations and I might not to do a hard disagree if I did, but I don’t understand why they should be RG from the evidence provided…)
I think I’d trust description of appearance better than description of calls, given that the calls can be ambiguous (e.g. young American sound more similar to Fish) and that most people “know” that crows “caw” which might bias descriptions from newer observers. Although for appearance, plenty of people think that grackles are crows too…
Another recent related thread here: IDing observations by superusers - General