Would you really need it on merged Epochs (rather than do these checks pre-merging)? Even if you did, having the `ignore_channels` argument would not change anything for you (you would have to pick one epochs object I assume). For users that do not use the stim channel in Epochs like me ignoring it with the argument would make the function easier to use (the majority I would assume -- aren't the events that the Epochs are based on based on the stim channel in most cases? So those checks would be circular?).