I was going for a more direct analogue, and how inserting the ID is more seamless than a backend query, and how tampering with SSL is more technically interesti

I was going for a more direct analogue, and how inserting the ID is more seamless than a backend query, and how tampering with SSL is more technically interesting to me, but yes, you're right. Good point on how it would not be detectable. I wonder how many ISPs are doing it right now...