It doesn't even have to be sparsely used. Nor do the purchases have to be very big. At least not with my bank. My wife occassionally does gas samples for a testing firm. Fills up little one liter bottles with the three grades of gasoline and then ships them off. The firm requires seperate charge receipts for each liter bottle. She fills up three of those, at a little under a dollar per charge transaction (at least that's what it USED to cost!) and her fourth gasoline transaction for that same day is denied by the bank. She has been successful in calling the bank and having the daily restriction lifted on a per incident basis, but usually she just uses cash with seperate receipts after the CC starts denying.

I also had a $15 transaction denied to Russia. Perfectly legit, but the bank's software noted that I had never made an overseas transaction before and therefore denied me as a precaution (per the banks explanation when I called).

I guess all this fraud prevention is a good thing during normal times. But you've got a good point here - during times of crisis when you might be buying more than normal amounts of abnormal stuff in remote locations ... you might run into problems. Maybe you could call the CC company BEFORE making these charges and explain you circumstances.