Half of the time, you achieved no pun in the first place. You just used some idiomatic expression that coincidentally contains a word that relates more literally to the subject of your writing.
The other half of the time, your audience won't believe you: whether or not it occurred to you on your first draft, the pun was intentionally left in, and they know it because you drew attention to. You don't get to claim inadvertent cleverness in a final draft. You have to take credit or blame for everything that you published. It was all "intended", otherwise it would have been edited out.
And 100% of the time, it's a waste of your readers' effort to bother reading your self-congratulatory observation of what is, in any case, a trivial accomplishment.