If there was a precept that said, “Don’t pick your nose,” I think most people would just follow it. It sounds like a minor rule about decorum and few people were going to violate it anyhow.
The precepts regarding weapons and vegetarianism are so contentious that discussion between opposing camps is almost pointless. Within a camp, though, there is room for discussion. How should a Buddhist act for the liberation and enlightenment of all sentient beings?
The precepts regarding how the monastery will handle dinner invitations to monks. It looks that since monks couldn’t beg door to door, than lay followers would invite monks to eat. For a lay follower, these rules almost sounds like rules regarding a situation I’ll never face. The rule on setting fires, likewise, isn’t one I expect to ever face.
The rule on garlic. Without a motivation that hasn’t already been disproved in science, I can’t see anyone taking this serious, except out of a sentimentalism for tradition.
There are several rules that are rules about enthusiasm. (The rule on vows, which enumerates horrible things you’d vow you’d rather do than break your precepts) These seem to be sine qua non to the project. If you don’t have some level of enthusiasm for following precepts, you’d just abandon the whole project.
So in sum:
Some rules are minor. They ask little, they don’t ask for anything we weren’t already going to do.
Some rules are on the face, specific to monastic life or some uncommon scenario– such as being in a position to make a decision about agricultural burning or controlled forest fire burning, or the like.
Some rules seem unlikely to be taken serious in the modern context. There really is a animal rights movement and the BNS has several essentially animal rights precepts. But I’m hard pressed to imagine a modern person actually preaching the dharma to the animals, in the hope that it would prime their memories in the next life.
Some rules are given, if you assume someone who is interested in the BNS.