I don't know if this is a bug or a feature, but in my daily patrol of Bottleneck, I found some thief scents at what once passed for our vault. After being lead on a merry chase and thinking I'd found him several times only to discover it was a false positive, I finally found a lone cabin. I popped in, giggled at the hearthfire 'lock', and ran around to get free. When I force summoned him, it dropped an assault clue without any sort of warning. Turns out that someone from Bottleneck had already dropped a warning so it was a lot of work for nothing, though.
Mainly reporting it as it seems it might have been something that got overlooked (though if one is Ranging about anyway, I suppose the warning is superfluous). In any case, it seems like it should be possible to ID someone without dropping a clue (at least given that you can do so if they have a claim, though that may be unintentional as well).