The phrase "questionable practices" refers to activities or actions that are considered doubtful, suspicious, or causing doubt or concern. It suggests that these practices may not be ethical, legal, or trustworthy in some way. Full definition
Many families paid a heavy price because of questionable practices that led to last decade's housing crash. (simplifyingthemarket.com)
But more than 70 percent of the scientists stated they would be less likely to engage in questionable practices now that they've become aware of the problems they cause. (sciencenews.org)
Best practice: If you believe a business is engaging in ethically questionable practices, don't discuss it on social media. (nar.realtor)