I'm thinking that this initial fine might be the start of a longer strategy of getting these guys out of there. In the recent article below, Falk is suggesting that some sort of more organized occupation is in the works. I expect that, in the end, BLM would want to show that they took all available means to encourage the trespassers to leave on their own accord, before having them carted off in handcuffs.

Will Thacker Pass Be Another Keystone?