Has anyone else noticed that people sometimes get this the wrong way round?
E.g. 'She made a lovely pizza but I am a coeliac so I substituted it for a piece of cheese instead.'
What the person means to say is 'I had a piece of cheese instead' or 'I substituted cheese for pizza'.
For some reason I've seen this far more with the verb than the noun. If you say 'I got x as a substitute for y' I don't think people get that the wrong way round nearly as much.