I agree, wooddon... and, so does Carnival. Their dress code, described HERE
, specifically excludes muscle shirts, baseball caps, and shorts (other than long, or Bermuda style dress shorts) on what they call cruise casual nights. All types of shorts, as well as T-shirts, are prohibited on cruise elegant nights, as is sports and beach attire on any night. I agree that enforcement can be lax on any line. Yet Carnival's policy, as stated in the link on their Web site, does not permit very casual clothing.
So, now that we have the official policy -- directly from the source -- that should hopefully bring the end to debates over what Carnival allows and doesn't allow.