I herd one of the fare inspectors say that they are eventually going to get scanners to read a presto card so they can see if it's been used. Right now until presto is system wide you still need a paper transfer.
This seems wrong to me based on the fact that this is not stated as a rule anywhere--in fact, the TTC has large posters explaining how to use Presto up at Union, Spadina, and various 509/510 stops, and they all explicitly state that a paper transfer is ONLY needed if transferring to another route, and that simply tapping on the fare payment device is sufficient if not transferring. Additionally, all TTC/Presto staff that I have spoken to have confirmed this, so it's very odd that the fare inspectors would be saying differently, and especially that they would write tickets when people have been explicitly told they don't need the transfer.
I have a metropass myself but often travel on the 509 with somebody who uses Presto when possible and doesn't take a transfer (I've also seen less knowledgeable passengers do the same at the explicit and direct instruction of TTC staff aboard), and I had been getting worried they could get wrongfully fined. So, I decided to look at
TTC By-Law No. 1 myself to see if someone who pays with Presto and fails to take a paper POP receipt can be fined by a fare inspector onboard or when getting off the vehicle at Spadina or Union, and according to the bylaw there is nothing requiring you to have anything other than your Presto card. If they don't have readers, that's their problem, there's no section providing for any penalty against the passenger--they can write you a ticket but you can get it cancelled in court and possibly sue for deliberate criminal harassment. The section relevant is:
"2.6 When requested to do so by a proper authority, a person travelling on the transit system shall immediately surrender for inspection the fare media, an identification card or photo identification card under which the person is travelling." Fare media is defined as including an electronic farecard, therefore handing the inspector your Presto card is sufficient, and while they can say they don't have a reader and ask you for a transfer, you are under no obligation to provide one.
Good to see that they can't wrongfully fine people for that. Phew.