The Dog that takes you into the Bar

Two men are walking their dogs (a doberman and a chihuahua) when they say to each other "I'm thirsty." They see a nearby bar and walk up to it.
Unfortunately, there was a sign on the door that said NO DOGS. They thought for awhile to try to figure out what they should do with no luck. Suddenly, the man with the doberman said, "I have an idea! Do what I do."
The man put on his sunglasses, walked up to the door and tried to get in but a big muscular man stopped him. "Where do you think you're going?" asked the big man. "This is my seeing-eye dog." said the man hoping for good feedback. "Alrighty mister, go right in." said the big man. The doberman man walked in.
The second man slipped his sunglasses on and did the same as the first man. "Where are you going?" asked the big man. "I'm going into the bar, this is my seeing-eye dog." he said. "A chihuahua?" asked the big man with suspicion. The other man, playing his part yelled, "They gave me a chihuahua!?"