I have a few customers like that. They sign up, forget about it, then they see it on their statement and issue a chargeback. Not only do they get their $20 back (that they very willingly signed up for), but I have to pay another $35 to Stripe for the privilege of having a forgetful customer who couldn't even be bothered to email me for a refund.
> I have to pay another $35 to Stripe for the privilege of having a forgetful customer who couldn't even be bothered to email me for a refund.
I've seen some businesses send a pre-billing email telling customers that they'll be charged on a certain date, so that customers have time to cancel if they want.
Cloudflare does that for domain renewals, sending out emails 30 and 60 days before.
Of course, there are also some businesses that hope that customers forget that they're subscribed, so that there's breakage.