My response would be, "OK, walk me through the code, show me how and why it works, or if it doesn't (code from teh Internets is buggy), fix it." Anything higher than a junior position requires maintaining code as much as, or more than, writing it.

Maybe this points to a better class of interview questions: the interviewer supplies the broken algorithm, the interviewee supplies the bugfix.

You're correct, but generally when critical thing X is broken and you need it working for the customer, you give it to your more experienced devs, not the college intern.

True, but when I'm in a more senior position, we're less often in a situation where critical thing X is broken.

"oh, you can use google. Surely none of the other candidates could think of that"

If an interviewee had the stones to try that in an interview, I'd probably have to at least give them a golf clap.