But then last week, a lesbian complained that an usher at Safeco Field asked her to stop kissing her date because it was making another fan uncomfortable.
The incident has exploded on local TV, on talk radio and in the blogosphere and has touched off a debate over public displays of affection in generally gay-friendly Seattle.
"Certain individuals have not yet caught up. Those people see a gay or lesbian couple and they stare or say something," said Josh Friedes of Equal Rights Washington. "This is one of the challenges of being gay. Everyday things can become sources of trauma."
As the Mariners played the Boston Red Sox on May 26, Sirbrina Guerrero and her date were approached in the third inning by an usher who told them their kissing was inappropriate, Guerrero said.
The usher, Guerrero said, told them he had received a complaint from a woman nearby who said that there were kids in the crowd of nearly 36,000 and that parents would have to explain why two women were kissing.
"I was really just shocked," Guerrero said. "Seattle is so gay-friendly. There was a couple like seven rows ahead making out. We were just showing affection."
On Monday, Mariners spokeswoman Rebecca Hale said that the club is investigating but that the usher was responding to a complaint of two women "making out" and "groping" in the stands.
"We have a strict non-discrimination policy at the Seattle Mariners and at Safeco Field, and when we do enforce the code of conduct it is based on behavior, not on the identity of those involved," Hale said.
The code of conduct - announced before each game - specifically mentions public displays of affection that are "not appropriate in a public, family setting." Hale said those standards are based on what a "reasonable person" would find inappropriate.
Guerrero denied she and her date were groping each other, saying that along with eating garlic fries, they were giving each other brief kisses.
On Tuesday, Guerrero said a Mariners director of guest services had apologized to her. The team spokeswoman could not immediately confirm that.
After the story broke, the Mariners were blasted by the sex-advice columnist Dan Savage, who wrote about the incident on the blog of the Stranger, an alternative weekly paper.
"I constantly see people making out," Savage said. "My son has noticed and asked, `Do they show the ballgame on women's foreheads?"'
Savage called for a "kiss-in" to protest against the Mariners.
Web sites have been swamped with blog postings for and against Guerrero and her date. And the story has people talking in Seattle.
"I would be uncomfortable" seeing public displays of affection between lesbians or gay men, said Jim Ridneour, a 54-year-old taxi driver. "I don't think it's right seeing women kissing in public. If I had my family there, I'd have to explain what's going on."
"It all depends on the degree," Mark Ackerman said as he waited for a hot dog outside Safeco Field before Wednesday's game. "Even for heterosexual couples."
Since the incident, Guerrero's job and her past have come under scrutiny. She works at a bar known for scantily clad women and was a contestant on the MTV reality show "A Shot at Love With Tila Tequila," in which women and men compete for the affection of a bisexual Internet celebrity.
"People are saying it's 15 more minutes for my career," Guerrero said of the ballpark furor, "but this is not making me look very good."
In 2007, an Oregon transit agency chief apologized after a lesbian teenager was kicked off a bus when a passenger complained about her kissing another girl.
Also in 2007, a gay rights group protested a Kansas City, Mo., restaurant they said ejected four women because two of them kissed, and a Texas state trooper was placed on probation in 2004 for telling two gay men who were kissing at the state Capitol that homosexual conduct was illegal in Texas.
"There's a double standard. That's the bottom line," said Pat Griffin, director of the It Takes a Team! Education Campaign, an initiative from the Women's Sports Foundation to eliminate homophobia in sports.