I find that surprising. The advice I've gotten from everyone when interviewing at the big tech companies in Seattle is always "make sure you clarify ambiguity before writing any code".

I always assume that part of the evaluation is on my ability to resolve ambiguity, and always try to clarify anything I can, sometimes including writing out an example or two and verifying we agree what the expected output should be.

to be sure it wasn't writing code - whiteboarding code/pseudocode. it was a bit of an ego stroke, i think, but given the state of their company at the time, and how they advertised the position, i don't suspect they were getting many sr-level developers applying. i applied mostly cause it was close to home.