What I usually do in a case like this is just talk. Ask them to show you what they have done. Ask them why they did it like that. Ask them the the advantages and disadvantages of doing it like that. Be nice and don't come across as a jerk. Come across as trying to learn rather than trying to trap or 'catch' them in something. I've found legitimate people who know what they are doing are usually more than happy to explain themselves. Good luck.