Daryl listened to what Dumbledore had to say, at the same time he was watching Hill and noting all that she was doing. While he knew the difference between say diesel and unleaded fuel, he wasn't knowledgeable in explosives. All the same, he had a keen nose, and could differentiate between smells with reasonable accuracy.
"I can smell 'em," Daryl shrugged. It didn't seem like a huge thing to him. Anyone with a nose would be able to smell fuel.
There was no way in hell Hill was putting a blindfold on him. It was one thing to stumble around in the darkness trying to avoid zombies, it was a whole other beast to allow someone to purposefully blindfold you. Daryl wasn't about to consent to that under any circumstances.