That is my experience as well. I have heaps of 'Masked Email' aliases for my Fastmail email account and the only significant offender I've come across is variou

That is my experience as well. I have heaps of 'Masked Email' aliases for my Fastmail email account and the only significant offender I've come across is various Kickstarter projects (as I understand Kickstarter passes on my email address when a project is successfully funded) and various Bitcoin sites from back when I dabbled in Bitcoins. All other reputable companies have actually not sold any of my email addresses (including some I've noticed elsewhere in this thread accused of doing so, which I find quite interesting). I am now at the point where I'm considering migrating back the majority of my aliases back to firstname@lastname.TLD address for most things. It is more hassle than it's worth as I often forget I had a Masked Email and end up creating a second account. Also in-store if I need to provide my address it is awkward giving out what sounds to store staff like a dodgy address. Also when I reinstall my computer/phone/etc it's a hassle figuring out what login address I used for each site/app I have accounts with. I may use Masked Email only if there is a higher level of risk.