I've been thinking about Organ Donors

So, I was thinking about this the other day and perhaps I am completely off base however....  Is it ethical to be a registered organ donor if you are an alcoholic, a smoker, a drug addict or if you suffer from diseases that could affect possible organs to be donated?  What if you have a severe history of heart problems in your family - and you are an organ donor?  I guess you know... receiving an organ from someone else always poses a risk as do all medical procedures.  I don't think there are really any rules/regulations.... right?  I am genuinely curious if anyone knows....