If we're being honest with ourselves, the title of your original blog post ("Stripe is Silently Recording Your Movements On its Customers' Websites") is worded like they're being being sneaky and have something to hide.
I gave a lot of thought to how to word it to not project intention onto Stripe. But I did think one of the most important parts of the story was Stripe's lack of disclosure about the behavior.
I considered and rejected "secretly" and "surreptitiously" because they suggested intention. "Silently" was the best word I could think of to convey the lack of disclosure while minimizing judgmental undertones. I understand that it still does suggest something underhanded, so maybe it would have been better for me to omit the word entirely.