Is Gaius aware of any custom prohibiting the casting of spells in a house without the host's permission, as in this case? Did Gaius see any guards around the estate going in?
Further, Gaius gets the impression that Solomon Beard is noveau rich or he has extremely bad taste on account of the garishness of the sitting room. But considering that he is hailed as a successful merchant, his accumen should not be underestimated. The two traits suggests a possible surprise from Solomon Beard.