Unpopular opinion, but I really see no problem with this? They aren't reducing the capabilities of the drive or anything. Three years is a damn good time to have a plan. Whether it be validating your backups, having a hot spare on standby, or double checking your RAID status.
More importantly, for the average consumer who doesn't maintain off site backups and may not have their NAS configured correctly to prevent data loss, giving people a head's up that they are hitting the warranty limit isn't a bad idea.
It's been a long time since I had a drive fail in just three years, but that's still all I consider a guarantee.
I could be wrong, but my understanding from Backblaze data/articles is that if your HDD made it past 1 year, it's probably going to last at least a decade. Drives tend to fail early if they're going to fail.
A warranty warning is fine, though still more obtrusive than I want personally. I haven't lost a disc at all yet tbh, including well over a decade of pretty hard use one several. I've got local parity and cloud backups for when that inevitably changes though.