I doesn't seem unreasonable to me to ask even a senior developer to do a small coding assignment as part of the interview process unless they can show a good, relevant coding sample.
If we're going to agree that whiteboard coding isn't a great way to evaluate someone, and we can't ask you to do an assignment on your own, what else is left? Talking about past experience is great and an important part of an interview, but I think most people want to (rightly so) see some code at some point before extending an offer.
