We know that bed bugs move further away from a host when suitable harbourage near the host is restricted. And if bed bugs are forced to locate harbourage far away from the host some get lost and will either disperse elsewhere or stay and wait for host cues to arrive. Sometimes the bugs will wait for a period of time and then look for a host. All the above options are bad news though for different reasons.
When a suite is completely cluttered with books, old pizza boxes, papers, etc the bugs do not have to move very far away from the host to find suitable harbourage. An infestation can be well advanced in these settings and the bugs still do not disperse to other areas because of the abundance of nearby harbourage.
If all the clutter is carefully discarded the suite is relatively easy to treat. If the clutter is not discarded successfully eliminating the bugs is difficult.
The “benefit” of clutter is the flip side of artificially removing harbourage from the bed. If you restrict harbourage near your bed with encasements the bugs will naturally move further away from the host causing the issues discussed in the first paragraph. Strikes me as a bad idea. If the tenant insists on preemptively encasing the bed he/she could consider adding lots of disposable clutter to the bedroom as a harm reduction tool.