Miller Park, already known as "Wrigley North" because it's a 90-minute drive from Chicago's Wrigley Field, was predictably painted Cubs blue and white. The two lower decks were packed, but most upper deck sections were roped off because the stadium didn't have enough staffers on hand.
Most Milwaukee fans stayed home and watched their team complete a doubleheader in Philadelphia. Most, not all.
"We're going to be outnumbered," Salmon's husband, Keith, said. "But I don't care."
A few came anyway, though they were hard to spot. They came to witness baseball history. A similar occurrence took place in April 2007, when the Indians and Angels migrated to Milwaukee because of snowstorms for Cleveland's first "home" series.
"I wanted to go, seeing a Cubs-Houston game at Miller Park," said Vince Milisauskas, 15, of Kenosha. "That's a once-in-a-lifetime chance."
The scene inside the park was unusual, to say the least. Brewers apparel was given secondary status to Cubs hats and pennants in concession displays. One man was seen wearing an "I Like Ike" T-shirt. The video scoreboard in center field displayed Astros trivia questions.
For the dozens of Brewers fans in attendance, who do you root for? Milwaukee entered the night 6 1/2 games back of Chicago in the National League Central, but two games ahead of Houston in the NL Wild Card race.
A pessimist would give up on the division, focus on the Wild Card and pull for the Cubs. But, these are the Cubs we're talking about.
"Any self-respecting Brewers fan would want the Cubs to lose," said Jake Materna, 18, of Waukesha.
"We hate the Cubs -- anything that has to do with Illinois," Keith said.
Is there anyone willing to put the rivalry aside for one night?
"I'm more concerned about beating the Phillies," said Alex Della, 17, of Waukesha.
He's on to something. Philadelphia entered Sunday's doubleheader nightcap with Milwaukee one game back in the Wild Card. It's a race that could come down to the final game of the season.
Imagine a scenario that the Brewers nearly catch the Cubs, but fall one game short of taking the division. Milwaukee fans could cry foul over the Cubs basically getting two extra home games this weekend.
"It gives them a little bit of an advantage," Milisauskas said.
The teams tried to find a more neutral site for both teams, such as Minnesota's Metrodome or Tampa Bay's Tropicana Field. Logistically, it couldn't be done.
"How do you make it fair?" Cubs fan Dawn Mullard asked. "[Houston] came into Wrigley and swept us [two] weeks ago, so who cares?"
Good point. For every 100 Cubs fans, there was one Houston supporter, maybe. That made Scott Narep, 24, stick out like a sore thumb in his Astros jacket.
Narep drove up from Chicago with his girlfriend, who is a Cubs fan. What did he think of the situation?
"I think it's fair," Narep said, before smiling and adding, "because I get to be here."
What about for your Astros?
"It's not fair at all," he said.