After reviewing a possible scenario with User License Enforcement/Standard users utilizing the content search web part (CSWP) I noticed some interesting behavior. It appears that user license enforcement doesn’t enforce all standard features (MS forgot the CSWP). I have done extensive testing against Excel Services and Visio Services, which present a nice message indicating that you don’t have licensing to view that web part.
The Content Search Web Part cannot be added by a standard user:
BUUUUT it still displays for a Standard user! Possible oversight on Microsoft’s Part (And possibly unsupported??)