Why does it ask if I'm 'sure I want to buy from the Pawn Shop'? Is there a reason I shouldn't buy from the Pawn Shop? If it's the cheapest price, that's where I'm going. I don't know why I shouldn't, unless there's some reason I don't know of...
BE A GOOD COMMUNITY MEMBER AND ANSWER MEEEE! XD
Maybe the Pawn shop owner likes his items? I think it's a security thing the Subetan progarmmers did to make sure you didnt click by accident.

I don't know if this is the answer, but when I'm doing quests I get that 15% buff for NPC shops, so I'm thinking it's like "Hey if you buy from here you don't get the buff, do you still want to buy?" Because I've done that and I was like OH GOOD CATCH and bought from a user shop.
that made no sense, I'm sorry lmao.
Simple answer: because if it wasn't there, people would be complaining and asking why it wasn't.
Tedious answer: it's there to keep you from accidentally misclicking and buying something you A) don't want, B) can't afford or C) both.

Because it's probably the same script as the cw pawn shop, and you probably don't want to accidentally buy a cw.

The situation used to be entirely reversed.
It used to be that if you bought anything at all from NPC Shops, you'd have to haggle for the item no matter how common. The Pawn Shop wasn't part of the Shop Search queue, you had to go there and look through it if you wanted to buy from it.
There was much concern that the PS was getting no love and its stock was too huge, so it got added to teh SS. Then folks who'd never even heard of it before started complaining that buying from it was automatic, so the warning was added. (CWs a whole 'nother can of worms).
When Vending was being talked about being limited because "there were too many cheap items around" (a sentiment that I wholheartedly DISAGREE with) folks suggested that restocking altogether was too hard, so the haggle was removed from the low rarity items.
I started a Suggestion that all "are you sure"s be removed from purchase and the PS and got shot down. Users like this feature? It's not like you can't lose sP now by accidentally random clicking on just about anywhere on a SS page except that one PS line.