Requiring it without checking achieves little
A clause demanding renters insurance is standard and widely ignored. Unless a certificate is produced at move-in and the cover is maintained, the clause does nothing at the moment it matters. Asking for proof is the difference between a requirement and a sentence in a document.
Being an interested party means you are told
Where the owner is listed as an interested party on the tenant’s policy, the insurer notifies you if it lapses or cancels. That turns an annual promise into ongoing information, and it costs the tenant nothing to arrange.
It genuinely reduces your exposure
A tenant with liability cover means a fire they cause is pursued against their insurer rather than falling entirely on yours, and their belongings are their insurer’s problem rather than an argument with you. Both outcomes protect your claims history, which protects your premium.