Usability is an important factor for cross reality laboratories. However, after conducting a literature survey on the ACM Digital Library and IEEE Xplore, we were only able to identify 15 papers discussing the usability of cross reality labs, which in itself reveals a lack of focus on that topic. Further analysis on the papers showed room for improvement, e.g., most papers only used questionnaires, which do not allow for deep usability analyses. From the surveyed papers, we were able to identify a total of 26 factors which play an important role in usability for cross reality labs, categorised into technology, laboratory operation, and learning. Based on our results, we can conclude that usability research for cross reality labs is an under-researched area at the moment and would benefit from more focus.