Generic ethics question: what is an ethical level of risk to accept, and what is not?

Ethics is "either-or". Either something is ethical, or it is not. Take driving a car for example: It is ethical to put others on the road with you, and you with them, because provided you follow the law, you are not putting them at risk by your behavior. If your car fail and someone dies, there are no ethics involved.

risk probability only applies to groups of comparable things, not to individuals. it makes sense to say that within a large group of people one in every so many hundred thousand will die from being hit by a car; it makes no sense to say that a given person has a certain probability of being killed crossing a given street at a given time and place. the probability of dying crossing an empty back road is effectively zero, the probability of dying crossing a superhighway is fairly large, and both are affected by personal considerations (age, attentiveness, fitness - an olympic athlete has a much better chance at getting across a busy street than you or I do).

ethics has more to do with the 'rightness' of an act than with its probability of success. if it's morally wrong to cross the street, then it doesn't matter if the risk is too small to calculate - you still shouldn't do it.

An ethics question cannot be that "generic'.

Ethics is situational by its nature.

'Generally' you can accept any risk you feel is justified by the

probable reward, for yourself without an ethical problem

The trouble comes when there's risk to others.

(There almost always is, in our close knit societies.

Do you have the right to subject that driver to the guilt trip

from hurting you when he hits you/))