Note that some of these examples might not be suitable for discussion in the classroom…!
There are several examples where versions of ‘obscenity’ filters, or automated word-replacements using regular expressions, have gone wrong when a too-global fix is applied.
One of these arises from the determination that the word ‘butt’ is more appropriate than ‘ass’ (there’s a bit of a US bias here!). Care is needed when attempting to replace instances of ‘ass’ with ‘butt’ otherwise we might end up talking about clbuttical music instead of classical, and presidents that are buttbuttinated instead of assassinated, perhaps this news would be reported in the Buttociated Press. Read more about The Clbuttic Mistake (Telegraph, £). There’s also the well-known Scunthorpe problem.