My company doesn’t require receipts for anything under $50. $25 meal and $25 gift card. Not that I would ever actually do that. Besides the ethical issues, it’s not worth risking my job over piddling amounts like that.
Policies like minimum amount before receipt don't make a whole lot of sense in a lot of cases, since they incentivize unethical people to run up the tab to the minimum as much as possible.
I've worked at both kinds of companies (receipt and reimbursement vs straight per diem based on location) and much preferred the one that handed me my per diem as cash in an envelope before the trip started. Less bookkeeping on the company's end, and if I decide to be frugal on the trip for whatever reason I've just rewarded myself with a small bonus. Seems like everyone's incentives are aligned in that case.
It is sadly too common for people to feel vindicated and/or thrilled anytime they manage to "win" like this, akin to the so-called beggar mentality, where any material gain to oneself regardless of actual need is considered a positive.
These kinds of people like to think of themselves as smart when in reality they are just selfish.
Any action that cannot sustainably be extended to everyone else in the world should be considered suspect as to whether it's actually good.