I don't think putting your licence number in to receive an update would be a big deal, to check it against one of your registered IP's...
This bit is a bit worrying...
Example Email "Hello, <username>. Your license will be revoked at <date>"
So the question is, where have they got the email addresses of licenced Construct users? and how do they know your username?
Nobody wants DRM, but who wants Scirra being bled dry by scammers?