Voldemort and Slytherin

[Tom Wall <thomasmwall@yahoo.com>]

No: HPFGUIDX 50773

"Slytherin, according to the legend, sealed the Chamber of Secrets so 
that none would be able to open it until his own true heir arrived at 
the school." Professor Binns (CoS 151)

Does anyone have any idea why Slytherin's descendants weren't watched 
with the utmost scrutiny?

Obviously, the rumor of the Chamber of Secrets was enough to cause 
many wizards and witches to search for its location in the school.  
In other words, they took it seriously enough to believe it might be 
there. So, if they took it seriously enough to entertain notions of 
its existence, how come they didn't take it seriously enough to trace 
Slytherin's lineage through to the present day?  

After all, Riddle's mother would have also been a descendent of 
Slytherin. In fact, there were probably tons of descendents of 
Salazar Slytherin. There are any number of generations between 
Slytherin and Riddle. And the likelihood of there being a single-to-
single family tree is pretty minimal, I mean, one-to-one all the way 
down *is* a fairly rare occurance. And although we don't know this as 
fact, we must assume that some, if not all of them attended Hogwarts.

So with all of those generations of little Slytherins bouncing 
around, why was Riddle the only one to open the Chamber of Secrets?  

I can only settle on three solutions:

1) Slytherin's descendents didn't attend Hogwarts until Riddle did 
(this seems totally ridiculous to me.)
2) The other descendents didn't figure out that they were Slytherin's 
heirs (this also seems silly to me.)
2) Riddle was the only one who was a Parselmouth, since that's 
supposed to be a very rare ability, so it's possible that none of the 
other descendents possessed the skill.

I like three the most, but it still doesn't settle well.

All the same, it just seems, well, *irresponsible* to not follow all 
of Slytherin's descendents very closely, particularly if they 
attended Hogwarts, knowing that there was a potential for said 'heir' 
to unleash evil upon the school.

-Tom