...
If there are charges associated with a researcher's use of the IdP of Last Resort, some percentage of them will simply refuse to use it, thus thwarting the SPs goal of making their service available to all its potential users. Further, many projects funded by national agencies such as the National Science Foundation cannot operate in a mode where users must pay a fee to access the project's resources.
R15. The IdPoLR service shall employ techniques to minimize system failures and ensure that any failures are not likely to result in inaccurate Assertions being sent to SPs.
...