Definitely!!!

No “might be” about it.

Not that they have a problem with lawbreaking.

I guess it should be more broadly to capture any identifying insignia or lettering (some have names and numbers on the uniforms).

Lots of people are taking excellent videos and pictures. But few of them focus specifically on how to identify ICE agents. This information exists in DHS now. But it is going to take a whistle blower or good crowd-sourced data to track down incidents that involve specific agents.

and shoot them in the face with mace.

...agents are swapping plates on their vehicles. A better approach would be to record VIN numbers, since those cannot change (and are found in multiple locations on the vehicle). I know that mechanics and car rental agencies have electronic readers that can scan a VIN number instantly. I don't know if that sort of thing is available to the general public, however.

The same VIN number is often found on doors and fenders too (none of which are visible). The VIN number shows up on major electronic components in the vehicle too. But, you have to access it through the onboard diagnostic port (OBD port) with a code reader or find someone who can hack into the vehicle's communication system. NPR had a story a few years back where someone hacked a Toyota Prius and was able to turn it remotely and shut it down as it was being driven. The police also have electro-magnetic pulse (EMP) devices that disable the ignition systems on vehicles. But you rarely hear about these devices being used.

By-the-way, it is possible to change the vehicle's VIN number in the computer and on-board electronics (have done it myself to solve some vehicle communication problems after swapping out the vehicle’s engine computer).

I forgot about the OBD approach. I see the mechanics and the AAA service techs using those scanners to read the VIN from the dash; there is supposedly an app that gives smartphones the same ability.