Iran's terms are all ships transiting the strait have to coordinate with its military. One would assume they are monitoring ship movements, and know which ones are complying and which ones are not.
The US doesn't need to "side with Iran" on anything: ship captains, owners and insurers are free to gamble their ships and payloads against Iran's resolve and strike capabilities, my assumption is they like to predictability make money, and not losing customer's billion-dollar payloads is part of that.
Having your ship blown up won't guarantee the US will consider the ceasefire violated, history is littered with post-armistice engagements and deaths.
