SideCar and Lyft, two competing apps that allow citizens to offer rides in exchange for donations, will both be out in force at South By Southwest Interactive in Austin this year — even though local regulators have said that ride sharing apps are illegal in Austin.

But while SideCar will be taking payments and arranging car pools, Lyft will be doing something else: piggyback rides.

Log into the Lyft app during SXSW, and you'll see up to 20 Lyft "piggybackers" who will be shlepping attendees around during the conference. Book a ride, and the piggybackers will arrive with pink moustaches, pink balloons, the signature Lyft "friendly fist bump," and a gift.

"It's just kind of ridiculous that there are piggyback rides on demand," cofounder and COO John Zimmer said. "It's just a good word-of-mouth, lots of buzz, people taking photos on piggyback, and people just having fun and learning about the Lyft brand and the Lyft experience as bringing people closer together... this all literally piggybacks on our messaging and our brand."

The company assured The Verge that all piggybackers, like Lyft drivers, have all passed a background check.

One of Lyft's competitors, however, has decided to brazenly flout the city's ban on ride sharing apps. SideCar, which recently acquired an Austin-based ride sharing app called HeyRide, announced its Austin launch today. SideCar is a bit further along than Lyft, having launched in five cities with Chicago and New York on deck.

In addition to offering to match drivers and passengers for donations, SideCar will be providing free transportation for some of the hottest fetes of the week including parties hosted by Tumblr, Twitter, and Spotify. The goal is to get people to try SideCar and then go home and keep using it, cofounder and CFO Nick Allen said.

"The dream outcome after SXSW is that we're looked at as the number one standout app of South By," he said. "Kind of like Twitter was in 2007. That would be great for us."

It can be tough to get around at SXSWi, since the startup and app-happy tradeshow brings more than 24,000 entrepreneurs, investors, and digerati to town for five long days. Given the swell of people and the number of events, you'd think an app to facilitate ride sharing would be a welcome decongestant.

The city of Austin does not agree. All taxis, pedicabs, and limousines must be regulated and permitted in order to operate in Austin, so empowering anyone to be a cab driver is expressly against the law. SideCar's "damn the man" style echoes the strategy employed by fellow transit innovator Uber, a taxi and limousine-ordering service that has clashed with regulators in multiple cities.

After the city of Austin said its piece, SideCar's CEO Sunil Patil wrote a blog post entitled, "Do You Believe in Sharing?" "We firmly disagree with The Austin Transportation Department’s contention that SideCar is an illegal taxi service or that people who use SideCar... to get matched for a shared ride are criminals," he wrote.

SideCar may win points and headlines for defying authority. But the city has said it may use the apps to get rides, then issue fines and citations to SideCar and its drivers. As dorky as it is, Lyft's cutesy publicity stunt may prove the wiser strategy.