First, not all illegals are of one race. Quite a few Russians and Irish now in the country that have crossed that SAME border,
I just said for me, if someone can not speak English, I am going to at least consider it possible they do not belong, and check.
heavily accented English, different story, but still, worth a check,
Someone who has native English, I doubt I will check.
Does not the law say "someone they suspect..."
Speaking, Native and Fluent English is not going to make me think they are illegal, regardless of race.