Alternative export tool, doesn't require login, open source and can be trivially rehosted by anyone if the traffic overwhelms:

Source: https://github.com/duggan/instazip

"Demo" (aka, you can use this unless traffic kills it): http://instazip.orchestra.io/

Caveats: bit buggy, running on a free Orchestra plan, wants a very recent browser to run.

PRs obviously welcome/sought.