Owls winger Ross Wallace made headlines on Sunday when a clip of him seizing a note, which was being passed among Huddersfield players during his side's win at the John Smith's Stadium, was widely shared on social media.
Carvalhal, however, is encouraging of such acts, it seems.
"We are teaching the players to do that - Portuguese style," he joked during Monday's pre-Cardiff City press conference. "We instruct the players to try to know everything about the (opposition) players, to hear the conversations between them, and stealing the papers is something (for which) we are training all the time because we want all the information.
"So if you want all the information, you receive information. Immediately, he said what was on the papers. It was good."
When asked what was written on the note, which was passed from Terriers boss David Wagner to striker Elias Kachunga via substitute Michael Hefele, Carvalhal replied: "Nothing - I’m joking!"
Wednesday claimed their fifth win in seven games against Huddersfield, who were the Championship leaders heading into the weekend's round of matches, and second in a row away from home.
The Owls will be hoping to make it a hat-trick on Wednesday night when they travel to face early strugglers Cardiff.
Despite their lowly position, the Bluebirds promise to be difficult opposition, having beaten promotion-chasing Bristol City in their first game under new manager Neil Warnock on Friday.