This is a story about kindness, good deeds, and great outcomes.

It starts with Rodney Smith Jr., who mows lawns for a living -- and who just got a free first-class trip to Alaska and Hawaii courtesy of Delta Air Lines.

As you might imagine, there's a bit more to the story. 

Mowing lawns in 50 states

As Smith told me Friday, this all began in 2015.

He was living in Huntsville, Alabama then, finishing up a computer science degree at Alabama A&M University. He happened to drive by an elderly man struggling to mow his lawn.

Smith pulled over and offered to mow the man's lawn. He was so grateful, Smith said, that he decided to start volunteering to mow lawns for other needy people.

He posted about it on Facebook, and the whole thing took on a life of its own. His amateur effort grew into an organization funded solely by $60,000 a year or so in donations. He's traveled around the country a few times.

This year, he got the idea to mow lawns for veterans in all 50 states.

He ticked 48 states off the list over a little more than a month. But then he ran into two problems: Alaska and Hawaii. 

Hey Delta, can you help?

Smith is humble and hard-working. He's also extremely media savvy. His social media posts get a lot of interaction. He got the idea to tweet at Delta and ask for help.

I talked with Delta. A spokesman said they saw Smith's tweet and decided to help out.

As they formulated a response, a summer intern from Huntsville spoke out on his previous efforts, reaffirming their decision.

Here's where I think this becomes interesting. Because a lot of brands get asked for freebies all the time.

Sometimes, they respond -- but it often seems like a calculated response, intended to boost the brand or get some solid public relations out of the deal.

In this case however, Delta's response seems more authentic.

Immediate result: A couple of first class tickets for Smith, that took him from Huntsville to Atlanta, to Anchorage, to Seattle, to Honolulu, and back to Atlanta and Huntsville. Smith tweeted and posted about the whole trip, including the veterans whose lawns he showed up to mow.

Ultimate result: thousands of good media mentions for Delta (I count more than 8,000 in Google News -- make that 8,001 with this one), along with probably millions of people having a fleeting, positive interaction with the airline.

The only way to do the math

There are a number of companies right now, all pitching stories and clamoring to become known as the "Uber of lawn care" in the United States.

But it's Smith who manages to get all this attention, and Delta that figures out how to become involved. How does that happen?

There's always a part of me that wants to open a spreadsheet and figure out the cost and the benefit in stories like that. And we can do that, pretty simply.

Let's guesstimate that it cost Delta something like $10,000, in the lost opportunity to sell those first class seats to Anchorage and Honolulu and back. But balance that against the earned media, and it's an insanely positive return on investment.

Except for one thing: I don't get the sense at all that this is really an investment.

I certainly don't think Delta has a room full of people sitting there in Atlanta with spreadsheets doing the math the way I just did it.

The secret this all reveals is that this kind of thing only works is if you don't do the math -- if you've successfully built a culture in which people are empowered to help out with small acts of kindness, and the authenticity comes through.

And that's a lesson for anyone running any kind of business.