It's there because that's how the C version has done it before (but that was changed in 5.9.2). See http://guest:guest@rt.perl.org/rt3/Ticket/Display.html?id=27606.

However, the C version was in fact also changed in 5.8.5 and above, so to be consistent, that line should return true for 5.9.[01] and 5.8.4 and below.

Update: if the above link doesn't work for you, try http://rt.perl.org/rt3/Ticket/Display.html?id=27606 instead, and specify username and password as guest.