If I attend the Memphis in May or the American Royal barbecue contest as a spectator, will I be able to taste the food made by the pit masters?

No. Regulations prevent the teams from serving the public. However, if you make friends with one of the team members, you may be invited to a private party at the team’s prep site. Again, that’s why the smaller local and regional competitions are so perfect for neophytes. You’re much more likely to be invited to taste the food.