I agree, nobody in their right mind would audit every such expense.

But he isn't being asked to sign that expenses are "essential or too trivial to audit" he has to sign that all expenses are essential.

>I agree, nobody in their right mind would audit every such expense.

I'll bite. Our money counters aren't in their right minds, because I submitted a small breakfast tab (at most $10) from work travel for reimbursement, only to learn it was unacceptable to not include a receipt. My other meals had receipts, but I had forgotten to ask for one this time. The accountant then said I had to call the cafe for a receipt. Luckily, the place had a website with contact info, and there was a helpful employee who emailed me the receipt.

But I spent at least an hour talking with the accountant and getting the receipt. The accountant spent probably 30 minutes with this problem. It was a net loss.

Obviously, I work in the government.

In that context, it IS essential: We need the item, and it's cheaper to buy a new one than to figure out if we already have one.