I've witnessed this first hand. For a nonemergency even. A friend with bad English went to the ER to have a rash looked at (not understanding what the more appropriate action would have been).

The ER don't doctor spent about 2 minutes with her and wrote a prescription for some topical thing.

Later the hospital sent her a bill for about $1500. I went with her to the hospital's billing Dept, helped her fill out a form that basically said "I have no insurance and no money".

The hospital ate the bill.