Slytherin's heir or Gryffindor's heir?

[romuluslupin1]

No: HPFGUIDX 113615

Old Salazar built the COS, right? Only his heir could open it, 
right? So how come both times it was opened a GRYFFINDORE was 
suspected? WE know it was opened by TMR (both times) who is 
Slytherin's last descendant/ancestor, and so does AD, but the rest 
of the students/teachers suspected Hagrid (a Gryff) and Harry 
(another Gryff). Ok, Hermione says that Harry *could* be Salazar's 
(x-times)-greatgrandson, after so many years (and this applies to 
Hagrid as well), but shouldn't this have raised some questions? 
Wouldn't a Slyth have been more likely to be suspected, at least 
once? I can see Harry being suspected, since he was a parselmouth, 
but I agree with Diary!Tome (shudders)Hagrid was a really unlikely 
culprit.

Romulus Lupin, who thinks this definitely proves the WW doesn't have 
a lick of sense.