Its not standard, its just one more thing that has been forced on tenants in some cases. The agents will insist it is standard, as they work for the landlord. But most agents are brain dead, dishonest little pricks. I would say refuse to agree, its a lot of hassle when you actually have to do it.
Many landlords don't have their own contracts written in stone either. What they would have is a standardized generic contract, given to them at some point by an agent - perhaps tweaking a couple of terms if it is personally important. That would the basis guideline, by which they assume tenants abide by.
This would be touted as a general checklist. How anally it is adhered to again varies from agent to agent, landlord to landlord.
That would the general guideline, by which they assume tenants abide by.