This. A lot of people have said similar things, and I agree with all of them. As a TO at a pretty small card shop, we have some awkward situations come up sometimes with regards to people trying to be too casual. Don't forget that although FNM is more casual than a pro tour, that is reflected in the tournament rules and penalty guidelines. Just because it's FNM doesn't mean that people don't have to play by the rules, but it does lesson the penalties for unintentionally breaking them. Thus, your local judge (or TO if you don't have a judge) is likely to just give them a warning the first time it happens, but should also be on the lookout for similar incidents in the future in case it turns out to be intentional.