I would think that the Hushmail question and answer is more secure.
If someone else got the link couldn't they click it and click the birds?
Having to know the answer to a secret question seems more difficult to crack.
FWIW, though I'm really rather ignorant about such things, I tend to agree with you. In fact, I sent the link from PH to my Ymail account. Then I forwarded it from there to my FastMail account and copied-and-pasted the link from FM into the PM I sent. So, while the actual
reading of the message may be in a secure environment (at PH's website), that doesn't negate the fact that anyone who could somehow intercept the
link in transit (e.g. as I sent it from PH to Ymail or from Ymail to FM) or who could find it in someone else's email account via hacking could, indeed, access the "private" message.