As someone who has travelled a fair bit across the border between Canada and US, CBP agents have always tended to be dicks drunk on their power. I've seen plenty of blatant abuse at the border. So really the only thing that needs to happen for CBP to ruin your day is for an agent to have a bad day for their own. The only difference between then and now is that they're given more tools to do so and actively encouraged to use them.