Would you still be kind if no one was watching?

It was a windy day today. Just before going to work today, I had to stop at the ATM. I parked my bicycle and got into the ATM. I did what I had to do and came out.

As I came back to my bicycle I saw the wind and knocked down a bicycle. Not mine but someone else's. The owner was nowhere to be seen. I looked around for a few seconds. Then before leaving I decided to pick up the bicycle. Put it upright again. And left the scene. As I was riding to my work I was thinking, that person will probably never know what just happened. He won’t ever know the small act of kindness I did. He might never know but it does feel good.
I continued pondering on this event rest of the day. I was thinking how many people would still be kind if no one was watching? Nowadays thanks to social media you see lots of acts of kindness online. Some of them are real and some of them fake. It’s hard to tell which are real and which are fake. In addition to this, how do you define what’s real? If someone is being kind to someone else so that he can gain something in return, like social media clout, is that still kindness? Or does it need to be selfless? I believe that doing any act of kindness gives you an immediate return of fulfillment and happiness, which is something you gain. So even in its purest form there is a certain give and take. So should we judge people if they still do it for gaining something more materialisitc?
I am not sure about the answer to that. But that’s what I thought about a lot today. Personally, I believe a kind act should be selfless and the warm feeling you get in your heart is something sacred. Doing it for materialistic gains or social clout won’t ever replace that feeling. Hope you do a small act of kindness every week. It’s a nice habit to have.