There are currently three forms of URL that behave differently with respect to authorization:
1. The presentation list and preview urls use /portal/tool/<tool-id>/... format, but passes through the portal and attempts to establish site membership even for public portfolios, which invites mistakes from users. That is, copying a URL from the list link and giving it to a non-site member does not work.
SAK-16425 supports the /access/... format, does not require authentication for public portfolios, but imposes an additional redirect
3. The public URLs use the formation /osp-presentation-tool/..., and does not require authentication for public portfolios
The portfolio UI should use the 3rd format everywhere as appropriate.