Sony revealed that they teamed up with Ys Net to help make Shenmue 3 a reality and then stated that they wanted to gauge fan support of Kickstarter to gauge the interest in the game. At face value, that seems like an unethical use of Kickstarter. It has been revealed, however, that Sony's role in the project isn't quite what it seemed.
The Shenmue 3 Kickstarter was updated on the second day of the campaign with an entry on their frequently asked questions section that stated that there are multiple sources of outside funding available to the team, but Ys Net can't reveal them due to contractual obligations. It seemed that one of these multiple investors was Sony, since they showcased Shenmue 3 on their stage at E3 and confirmed that they are helping with the game.
However, according to Sony Vice President Adam Boyes, their involvement in this game was simply to provide a platform to advertise the game at E3 and to help with marketing. So, their comments about wanting to gauge fan reaction to the Kickstarter aren't unethical, as they simply have to do with how they market the game for Ys Net, and that's a perfectly reasonable approach toward the Kickstarter campaign when your role in the project at that point is simply as a marketing firm. Sony is not even contributing money towards actual development costs of Shenmue 3 at this point.