@Shopaholic from what I gather Reader for PC will still be able to be used until and unless everyone is compelled to use ADE3.
I don't intend to upgrade Reader for PC, so it will stay on ADE2 authorised and I can continue to download ADE3 and ADE2 epubs.
Reader for PC software sits wholly on my PC - it does require an internet connection for downloads because it auto authorises Adobe, so as I say, provided I don't upgrade it I should be good to continue using it until it no longer authorises ADE2 ebooks.
I'm far from clear on all this ... these are just my thoughts ....
Edit
That's why I've suggested to others that they open an Aus or GB or wherever Sony Reader for PC account and continue to use it. One doesn't have to enter their payment details in order to open the account.