In its mobile coupon tests in San Diego, quickie-market 7-Eleven is getting into ethical — lukewarm bubble-bath water — over its accidental underage audience.

While mobile promotion seekers have to opt-in to the mobile ads, in collecting phone numbers and e-mail addresses some say that companies need to be careful not to target children when the messages are more appropriate for adults.

StorefrontBacktalk’s Evan Schuman’s write-up on the 7-Eleven trial has brought the issue to light, saying that since the trial doesn’t ask for ages, it would be best to “treat all of participants with… kid gloves,” continuing, “that approach certainly seems safer than assuming they are all adults and risking parental wrath for marketing to a 14 year-old.”

GMR Marketing is running the campaign for 7-Eleven. GMR’s senior vice president TJ Person responded that when the company asks for an opt-in, they assume the user is more than 13.

But how much trouble could a retailer get by trying to court target customers who are underage and offer them free sodas? If anything, this reminds mobile marketers to be careful when it comes to mobile marketing campaigns that could accidentally target an underage audience.

The trial began Nov. 1 and concludes Dec. 31,  although Daniel May, 7-Eleven’s marketing manager in charge of the trial, said the chain may continue testing mobile coupons outside the San Diego area in 2010. Person told CBS News the trial was done as a strong opt-in campaign, which should minimize later complaints of unsolicited ads. The consumer must initiate the trial by texting a message-“FAST”-to 72579. Consumers are then told they’ve been awarded a free beverage (Slurpee, Big Gulp or coffee). Once the consumer shows up at the store, that they are offered two ways to redeem the chosen beverage.