I'm willing to accept that not every instance of cheating is necessarily clear cut -- that there may be some iffy choices that have not been explicitly identified as out-of-bounds.
However, I keep running into a situation that is quite different, where an explicit rule has clearly been broken* and yet, the person who has been caught breaking it tries to persuade me not to impose the promised penalty for breaking this rule** because the imposition of that penalty will lead to other bad consequences for the person who broke the rule that this person really, really doesn't want to deal with.
And look, I understand not wanting to live with the bad consequences of a choice. But the very fact that X will bring additional bad consequences for you does not mean that X was not cheating.
Those additional bad consequences from being caught cheating should maybe have been reason enough to try to achieve your desired ends without violating the agreed upon rules. Gambling on achieving those ends by cheating only works if you get away with the cheating. When you don't, articulating all the reasons that being caught cheating is going to mess you up does not make what you did something other than cheating.
* For example, "Here are the resources you may consult to complete this assignment and all other resources are forbidden," or "You must properly cite the resources you used in completing this assignment." In practices, violations of the first rule here are always accompanied by violations of the second (since otherwise, you'd be acknowledging that you used a source you were not allowed to use).
** For example, if you violated the agreed upon rules, you fail the course. (Here, the students must explicitly affirm that they understand the rules and will abide by them at the beginning of the course.)