Unless we're specifically working on heelwork for part of a walk, which is rare, they aren't heeling. A loose 6' lead is fine, or if possible, they are off leash. They can sniff and do as they please, get recalled back into heel position for a stay if people come, or if they are leashed I ask for attention while walking by people, and they're expected to leave it when I say if they're hung up on sniffing an item.
Never had a problem.
I don't think it's very enjoyable/fun for either of us to have my dog staring at my face an inch from my pant seam when we're out walking in nature. XD They're good dogs - they earned the right to sniff and explore just like I am.