Under Gravy, a donor who starts a donation via PayPal but clicks 'Cancel and return to Wikimedia Foundation' is returned to a page stating that " There was an error processing your request.
There are other ways to give, including PayPal, check, or mail. "
We may need Gravy to change their code so we can tell when the donor clicks cancel, as the return value sent to us just looks like a failed authorization.
With our direct connection, when a donor presses the cancel button at a PayPal donation, we redirect them to the Ways To Give page. We could do that, or show alternate text for the error page that reads
"Your transaction was successfully cancelled.
Didn't mean to cancel? You can <a href=\"$1\">go back</a>, try one of our <a href=\"$2\">other ways to give</a>, or contact us at <a href=\"mailto:$3\">$3</a>",