random act of kindness?

so, my bike seat got stolen...yup.
i left locked up for a couple hours in the place where i usually leave it.
when i returned to it...something was different. someone had stolen my bike seat. but...there was a newer, nicer, more comfy bike seat on my bike....
what could be the explanation for this. my main theory was that someone had stolen another bike and wanted to make it less distinct.
but with everyone i've told about this, their first response is
"random act of kindness". i love the optimism in this.
but really...poor girl with the crappy looking bike...i think i'll give her my nice fancy seat and she can sit happily ever after on it...i dunno about that.