I worked once for a company who internally decided to never contact paying accounts that hadn't logged in in over a year. This isn't a gym membership, this is 5 digit yearly payments.
The reasoning? "We don't want them to realize they're paying us for a service they don't use and cancel."
The next step should be to transform "unethical" into "illegal", except enormous business entities rely on subscription revenue.
Otherwise it's a very well know effect. There will be unsubscription peaks every time the service communicates with thei customers, even purely informative stuff like "we now have a dark mode" emails will remind people they've a subscription and some will cancel, that's part of the business and something that affects communication frequency in subtle and obvious ways.
The reasoning? "We don't want them to realize they're paying us for a service they don't use and cancel."
I guess I see the point, but feels unethical.