I'd also been been worried about a similar requirement to ensure reviewers could have anonymous access to software run as a service. In that case even providing dummy accounts to the reviewers might not have been allowed (since the administrator could easily 'spy' on what the reviewers did or didn't try).
Given this potential barrier to publishing a paper using or extending Galaxy, I would hope extending Galaxy so that users can choose to share a workflow (or visualization) with anyone - even an anonymous user - would be a priority.
Is there a trello issue on this? Searching there isn't very intuitive to me... http://galaxyproject.org/trello
I've created a card for anonymous use of workflows and visualizations: https://trello.com/c/gja5TtwF Thanks, J.