I mean I get it. Sometimes fixing that evap leak isn't worth it, especially given how much of a pain it can be to find the source. I've ignored my fair share of check engine lights.

But a lot of it can be ignorance and/or laziness too. I fixed an airbag light once simply by disconnecting and reconnecting the wires under the seats. Apparently a weight sensor was malfunctioning but it was just a bad connection due to oxidizing wires. Took 30 seconds to fix, and an additional 5 minutes to look up the technique for clearing the code. But I'm wiling to bet that your average driver wouldn't even think to investigate. A piece of electrical tape over the light is so much simpler.