Trust is a fundamental building block of any healthy relationship, whether that’s between individuals or companies and customers. If you can’t trust the company you are doing business with to do the right thing by you, it’s hard to continue the relationship. Too often, we have seen this trust broken when it comes to data sharing.

Last week, a Wall Street Journal article revealed a practice of apps sharing highly personal data with Facebook without user knowledge, whether the user had a Facebook account or not. In a follow-up article, the WSJ listed all 11 apps in its study (five of which stopped sharing data after being contacted by the publication). These included ovulation and heart-monitoring apps.

Whatever the reason, if your users aren’t aware that you are sharing their data in this fashion, and that would appear to be the case, then it’s a gross violation of trust between user and brand. Marc Benioff, co-CEO and co-founder at Salesforce, has often stated that trust is one of the primary components of a healthy brand-customer relationship. If you mess that up, it’s going to be very tough going for you as a business.

In an interview in September with Bloomberg’s Emily Chang, Benioff had this to say about trust. “Every CEO needs to ask themselves what is the most important thing to you. What is the most important thing to your company? What is your highest value? I know our highest value at Salesforce is trust. Nothing is more important than the trust that we have that we have with our customers or employees or partners or our top executives,” Benioff explained.

He went on to say when companies misuse customer’s data, they are breaking that trust and that could involve losing key personnel or customers. “When you see top executives walking out. When you see customers questioning your privacy practices or how you’re using or misusing their data or how you’re misusing partnerships, you need to listen. You need to wake up. You need to [ask] what is going on. It’s very serious,” Benioff said

If Benioff is right, and trust is the basis of all business relationships, then you’re playing with fire when you abuse the trust by sharing data with third parties without your customer’s knowledge, and sooner or later that’s going to come back and bite you as a brand.

Let’s face it, people stop using apps for a variety of reasons that have nothing to do with something as fundamental as trust. It could just be buggy or slow, but when the app is sending data to another company without user knowledge, it’s easy enough to just remove it from the phone and find another one that doesn’t do that (or at least you hope it doesn’t).

For brands, perception is everything. If people begin to think you are not looking out for their best interests, or are putting profit over common sense protections, it becomes difficult to turn around those negative feelings once they begin to harden.

If the brand continues to abuse its users time and again, it will eventually have an impact on revenue and begin to hurt your relationship with your existing customer base, and your ability to attract new customers to your products and services.

It seems like a risk that would be too big to take, yet we see brands take these risks time and again. If you don’t want to go that route, it’s pretty easy to prevent. Do right by your customers and they’ll continue to believe in you — or don’t, and watch what happens.