Public services and maps do not require a SLIP account. You can simply click to open SLIP maps, or copy and paste SLIP service URLs into your GIS or other application.
However, if you would like to download this data you will need to set-up a SLIP account like the example below for Geodetic Survey Marks from Landgate:
Asking you to register (at no charge) to download public data enables us to understand who uses the data, and to help build a case for the release of more data publically.
You need a SLIP account to gain access to subscription and other restricted data via SLIP and for approval from custodians. Each dataset on Data WA includes contact details to request access to subscription and restricted data.