I would allow it at my office. The cork board I assume is for things important to them. I’m not going to take away something small and unobtrusive that they like. Especially because every time I thought too I was reminded of how it’s those things that make them personable to prospects.

I have a brand new leasing consultant who has a large corkboard next to her desk (provided by the company). 
Employees usually put a calendar, some photos etc. on the board - this board is visible to all who come into the office. 
This employee just put up some very large cutouts of Taylor Swift on this board. I don't feel this is appropriate/professional for my office but looking for the best way to communicate. Or am I just being too sensitive?