Why not both? Of course you can accept responsibility for this mistake but then suggest creating a testing suite to run commits through before making them live?
Yip, that's exactly what I did today. I made a mistake which borked layout on one page. I thought I'd looked at it, didn't, and it got deployed. I'm now suggesting the company use continuous integration and some automated screenshot type tests for catching these issues.
I hate making mistakes, but if more robust procedures are the result, well, it's an overall win!
