Well, people should be a bit more committed, and see the app, since it seems to be a big deal. This is probably also the fault of management for not engaging the employees more. Other than that, there's nothing wrong for putting out a good word for your employer. I'm sure every company does something similar, even if just by giving out shirts with the company logo. There's a fine line, and I'm sure plenty of companies cross over to the "wrong" side, but at least for me, it's not terrible, and to be expected actually.