The Redhat Certified System Admin, Redhat Certified System Engineer and similar tests require practical, general hands-on skills to solve broken systems. The performance tuning and troubleshooting exams go into more detail and more complex scenarios. No internet access, but resources are available if you understand how to use them. Would never suggest people should solely hire on those certs, but if someone takes the time to complete 7 hands on tests for the certified architect certification, it's a strong indicator they have skills.
Even so, test taking can be stressful but it's arguably less stressful than actual production support with people waiting on the result. Whether people really want to put candidates in a stressful situation is up to them. Sadserver seems like it's somewhere in the middle vs some of the things I've seen. One job interview put me in a room with a boot cd, and an ancient computer with a cdrom so slow you got exactly one chance to boot the media and recover the system in the time limit. But the job was for a trading company, so if you couldn't handle that they didn't want you. It was a fun exercise but would I do that to someone else? Probably not.