Conducting exams in which a computer (but no internet) is available
My university in the UK provides such "locked down exam mode". Students log in with special "exam accounts", while their normal accounts are disabled for the time being. Exam accounts have limited access to network, permitting access to the University network (including submission servers, licensing servers, and other necessary infrastructure), and restricting access to anything else. This has been working well for the last 10-ish years at least, and I have not heard any major complaints from IT staff about it. For comparison, the same IT staff found it difficult to install TexLive on all university computers and were reluctant to perform this task.