There are many ways to interpret the tax code; the IRS makes its rulings based upon "all facts and circumstances" which is why you end up with different outcomes for the dog breeder and the owner of the knocked-up mutt mama.
Bottom line, you need to decide if you are a business or not. If you are a business, and operating with a profit motive, taking a lot of reimbursement-only shops does not support that. It's a "circumstance" the IRS will consider when disallowing the deduction for the meal and turning the reimbursement into income, or declaring your enterprise to be a hobby and disallowing your net loss. By only deducting half the expense, you leave yourself some profit to support your profit motive.
It is up to you to prove your business status and profit motive. As to what to do with reimbursement-only shops already done... if you add everything up, they will get lost in the grand total. It's only a problem if you get audited and the details are examined. The method you choose will depend on how risk-averse you are.
I solve the problem for myself by not taking the shops. i have taken only two reimbursement-only shops, I did the first to get in with the company and to see what the shops were like. I had issues with the first, had to do a lot of explaining and correcting, and did the second to show i had learned and gotten it right this time (both were paid; the first was more trouble than it was worth because they wanted 'food critic' narratives and this was not clear from the instructions). I have not taken any since. I'm in this to make money, not to spend hours on a shop and report for a steak dinner I could make at home for less than $10 - the amount I can make on a 5 minute bank shop.
I'm not telling anyone what to do, just suggesting you think about how your reimbursement-only shops will look to the IRS on an audit -- and it will look like undeclared income -- depending on how many of them you do in relation to the rest of your shopping activity. for me, it was two shops out of 300 for the year. if some of you have 50 out of 200 shops in this category, you might want to rethink what you're doing and why.
Remember that the tax code was written, and will be interpreted by the IRS auditors, for the purpose of collecting taxes -- not for allowing people to collect a bunch of fringe benefits for free and avoid paying taxes on their other income (by taking losses).
Showing a profit in three years out of five will not exempt you from being audited, nor will it exempt you from being declared a hobby if your losses were $500 and $700 and your profits were $100, $25, and $50. "All" facts and circumstances will make the determination, not an arbitrary "rule of thumb" that is often quoted here. I could show any profit or loss I wanted on my return by claiming or not claiming expenses. The IRS knows this. They will not be fooled by creative bookkeeping.
Time to build a bigger bridge.