Won Fortix!

Err, report is if you think something is suspicious not only if you are 100% sure there is rulebreaking.

For example a while ago I saw a giveaway from someone that had won the game previously(a few days IIRC) and it wasn't in his library so I reported him as at the very least if he marked as received then he should have added to his library. A day or so later I noticed it was in his library so in this case there was no problem but I do know other reports that do end up with people banned so should I have done nothing because I couldn't confirm(impossible for me to confirm really)?

In this case he could have spent a few minutes(due to SG being slow as hell mostly) to check the description of the first one to see it was a beta key and then the date the game was launched to see if the latter could also be one but if you expect everyone to be willing to spend time looking at other users, check everything they might find odd AND have the time to do so then it is very likely the time taken to find rulebreakers will be high. Which would increase itself since if cheaters are common the rule abiding people get annoyed and end up not wanting to participate anymore leading to more cheaters which annoys people more and so on.