Hmm when we know where the one user case comes from then maybe having separate actions (like `single_email` and `mass_email` or something) would be better with the common code extracted. Then for the mass email the params key could also be called `:users` But I'm not totally sure.

However also with this approach I'd rather see this handled in a before_filter for the controller (logic should not be in the views). And as a shortcut you can do `Array(user)` (this make one element into an Array and lets an array be an array if an array is passed in)

Cheers and thanks for your work!
Tobi