When Americans see a Mexican, will they assume he is breaking a law by being here?

If this American watches Fox news they have seen people sneaking across the border, and Joe Biden talk about how America has to help people who are on the other side of the border.

The Mexican may say he has a green card but we will assume he is lying.

If they're white racists or Trump supporters, yes.

Otherwise, no.

What do Mexicans look like exactly? 

As a joke, yes, all the time. Realistically though I know most of them are here legally.

Apparently those living under rocks fail to understand that for the past 7 years it is not Mexicans, but Central and South Americans that have abused the border.

Nope....unless that person was seen illegally violating federal law climbing over or a tunnel under the border wall or just walking in where there is no wall.

I know for a fact that this one mouse i never got was Speedy Gonzales .

It got away always and went anony mouse 

I lived in San Diego for 30 yrs. I crossed the border many times and learned to trust/respect Mexicans to a higher degree than many Americans. When times were rough, I stood on the sidewalk in front of Home Depot w/ these people. I love them, I understand them. Today, I'm comfortably retired but I had to wait for the pension to kick in.