Oh, I hadn’t thought of it that way. You’re right, if in case they are using only some ID mentioned in the IMM 1017E form to track one’s re-medicals, then this could be an issue.
I had called up a hospital to book an upfront medical appointment yesterday and they only asked me to bring my passport. I remember when I went for my first medical, I too wondered how will IRCC know that my medicals were done since the hospital didn’t ask me for any IRCC-issued ID number. I even asked them that “are you sure I don’t need to provide any other details about my application”, to which they said “no, your passport number is all that’s needed”.
I am perhaps hoping lady luck would work her magic and I get sent an official re-medical request within a few days