When I helped my grand parents set up GMail they decided that they wanted one shared email account instead of one each. That has worked very well for them. Old people have enough to keep track of already so a shared email inbox for the both of them is great. My grandfather uses the GMail web app on his Mac desktop and my grandma uses the GMail app for iOS on her iPad.

However, when I set up Apple ID for each of them I wanted to create separate Apple IDs for each of them.

Thankfully Apple does not do anything like ignoring the + part you provide.

There are many ways spammers can create any number of email addresses.

Ignoring the + part of email addresses isn’t going to stop spammers, but it is going to cause a lot of pain for regular users because the + part has many applications that you can’t even imagine.

When the user hands you an email address, use that email address as is. Don’t ignore the + part of GMail addresses or anything like that.