>> Just a suggestion but make the canary/alias less obvious. Companies caught onto this and are treating aliases with their name in it as "fraud" which is of course a load of crap.

> It hasn't caused me any issues yet [...]

Ugh, I ran into this earlier this year when creating an Airbnb account. I tried registering with "airbnb_[randomcode]@[mydomain.com]" and was confused when account creation would error out with an unhelpful error message (don't remember what exactly). After checking with multiple browsers to make sure it's not some browser or uBlock Origin problem, I suspected it might have something to do with the "airbnb" in the alias. Sure enough, I created some temporary alias without "airbnb" in it and ... it worked. I wasn't willing to tolerate their sh— "load of crap" though, so once the account was created I tried to change the email back to "airbnb_[randomcode]@[mydomain.com]" and ... it worked. ¯\_(ツ)_/¯