How would you know they are 'serious' or 'avid'? A criminal is likely not to tell you the truth. Lots of criminals ride bikes, whether or not they tell you they are a serious rider or you find out for yourself, but I usually don't approach someone on a bike and ask if they are a serious cyclist I tend to mind my own business lol. If you are just talking about folks who are so into a particular sport that they can compete at a high level, then I'd say generally the same logic can be applied to most sports of this type. I don't think you'll find a pro marathoner, triathlete, swimmer, etc who is a career criminal or something like that lol, criminals are usually more about trying not to work hard.