Hagrid in Knockturn Alley ( WAS: JKR hints at secret)

[l3al3y_Doll_3]

No: HPFGUIDX 73810

I've been reading the "JKR hints at secret thread", and something 
kept bothering me. Quite a few people seem to be in agreement the 
important scene might have been Hagrid in Knockturn Alley, and 
doubting the reason Hagrid gave Harry. Now, my question is, why 
would he have lied? Why can't it be possible he was there simply for 
the slug repellent? Professor Sprout was probably planning the 
mandrake studies during the summer, and asked Hagrid to pick up the 
slug repellent for her.

I guess my point is I can't see another reason for Hagrid being in 
Knockturn Alley, as well as it being crucial to the whole series. I 
mean, it's been three books since then, and it hasn't been mentioned 
at all. This doesn't mean I think the theories are wrong, I'd just 
like to know the reasoning behind them, since there weren't any 
given.

Can someone better inform me with their views on this please?

-Maritza