Note: Started typing this before Zak posted, and Zak beat me to it, but I spent a good amount of time typing this so I'm posting it anyway. Consider any repeats agreement. :)
Emergency rooms are required to provide lifesaving care with or without insurance in the US.
They are not required to provide life-improving, or even life-restoring care. For instance, if you lose your finger, they are not actually required to sew it back on - they are just required to make sure you don't bleed to death from it. Do not take this to imply that most of them won't, but it certainly does affect the standard of care across the board, especially in underfunded hospitals.
Also, nothing requires them to waive the bill unless you are below a certain poverty statistic. The poverty line is, I believe, based on the minimum wage. So essentially, if you make above minimum wage, you are not considered below the poverty line, and not eligible for much of the aid offered. I went this last summer without a job and was still considered above poverty line because of my savings account. Now, there may have been some loophole or something that an experienced public servant could help me through (if I get a nice one who happens to be in a good mood and who has the time to be so helpful, assuming they have the knowledge in the first place) but I didn't actually apply for anything, only researched it, so I don't know for certain.
As for who's contributing and who's not, I'd prefer that people worry about those who are contributing and still not able to improve their situation. There will always be mooches - all you can do is try to minimize them. If you completely try to eliminate mooching, you end up with people who fall through the cracks. At the risk of sounding very 'what about me?!', I'll point out that students who try to work their way through school instead of staying in dorms and racking up more debt are, in the case of the US, pretty darn well screwed unless they really luck out on their job. In the current economy, that's highly unlikely. I know this because I attend school with thousands of people stuck in this situation. Student status is considered a handicap by employers, ending up as little more on a resume than a huge sign that says "Inflexible schedule". This bugs us.
Gun control is a different issue altogether, so the only thing I'll say about that in itself is that I have personally lived in right-to-carry states and pro-control states. I personally experienced more shootings, more gunfire, and... how to put it... more menacing gun presence, in the pro-control state. In the right-to-carry states, they're just there. Uncle George has his shotgun and probably a smaller gun somewhere (especially if he has a concealed-carry permit) but you don't worry about it. Whereas if you see someone with a gun in a pro-control state, they probably got it illegally unless they are law enforcement, which means that they can't, say, take it to the local firing range and learn how to use it properly. They probably haven't taken any courses in gun safety, probably have not been taught to keep their bullets and their gun apart when the gun isn't in use.
Gun nuts, I don't worry about, because they are the professionals of the shooting world, and know what they're doing. It's the people who get their guns furtively, without learning to respect their weapons, that I worry about.