Thundercles, Antistone,
I think your argument got heated up, because no-one likes to be unsportsmanslike.
And it is very well possible that what gaming group A thinks is normal is called unsportsmanslike by group B.
To make this more concrete: an example.
We used to play a lot of Risk with my family at home. Making no-attack agreements was 'not done' and would be seen as a kind of cheating.
When I now play Risk (the future version, but still the same ethics) with my friends, you won't be able to win if you do not make pacts with at least one neighboring enemy. In the first round someone offered me a pact and I was like 'yeah, right..". We both didn't win that game
Morale of the story: different groups: different ethics.
Looking at the Descent discard pile is not covered in the rules and is therefore subject to the ethics of the group. Any discussion on this can be good if people will throw in pros and cons, but everyone needs to respect other peoples views. What is unsportsman for you, can be be normal for another. So instead of calling that player unsportsmanslike, use the arguments (card counting) as a con.
However, I don't think Antistones group and Thundercles group will handle this issue ever the same (unless it would be included in the rules).
So please respect each others ethics/view on this one.
- my 2 cts