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(Telemachos:) ‘Suddenly you have changed, my friend, from what you were formerly; your skin is no longer as it was, you have other clothing. Surely you are one of those gods who hold the high heaven. Be gracious, then: so we shall give you favored offerings and golden gifts that have been well wrought. Only be merciful.’ (16.181-185)
Interestingly, Telemachos finds it more believable that Odysseus is a god than that his father has finally returned home.
Around him the haughty suitors clustered. They all were speaking him fair, but in the depth of their hearts were devising evils. (17.65-66)
Here's the difference between Odysseus's deception and the suitors': he devises ways to save himself; they devise ways to kill their host. Big difference.
(Odysseus:) ‘So I will tell you the way of it, how it seems best to me. First, all go and wash, and put your tunics upon you, and tell the women in the palace to choose out their clothing. Then let the inspired singer take his clear-sounding lyre, and give us the lead for festive dance, so that anyone who is outside, some one of the neighbors, or a person going along the street, who hears us, will think we are having a wedding. Let no rumor go abroad in the town that the suitors have been murdered, until such time as we can make our way out to our estate with its many trees, and once there see what profitable plan the Olympian shows us.’ (23.130-140)
Odysseus wants to trick all the Ithakans into thinking all the noise of the slaughter was the racket from a wedding celebration. How ironic, considering that was the very thing they wanted to avoid earlier.