shrooms is saying if kei ignores our thoughts and unilaterally informs ami, that breaks trust. he is not saying that that was kei's intent.
we could do a half test by having a blind (since they not allowed to see the seal) 7path summon use the telescope in the dragon/seal's general direction. if the telescope itself allows dragon teleport without even observance then they can die in kagome's stead.You're assuming that none of the Dragons have a 'exactly as far away as it appears' eldritch trick, where if you look at them through a telescope or something they're automatically close enough to touch you.