Just for the record, in case anyone was wondering, a valid eTA is canceled (in fact, erased from the record - it doesn't even count as canceled) when a person arrives in Canada to assume PR status.
I wasn't sure if it would be canceled or would slip through the cracks. It would be very handy for CIC to NOT cancel the eTA until the PR card has arrived, but it seems that there's no motivation to make the period of wait time for new PRs any easier while whichever outsourced company has the contract takes their sweet-ass time to make a dumb card. This basically ensures that new immigrants cannot take on any employment requiring business travel overseas until the random time interval for card issuance has passed. /rantover
I wasn't sure if it would be canceled or would slip through the cracks. It would be very handy for CIC to NOT cancel the eTA until the PR card has arrived, but it seems that there's no motivation to make the period of wait time for new PRs any easier while whichever outsourced company has the contract takes their sweet-ass time to make a dumb card. This basically ensures that new immigrants cannot take on any employment requiring business travel overseas until the random time interval for card issuance has passed. /rantover