Currently in Egypt and they just asked us to pay in USD cash for an added activity but, not being American, we don’t have USD. We have the local currency and the ability to get that out at ATMs, but no way to access foreign currency. So annoying but they accepted local in the end.
This happened to me in Laos (was it Laos? yikes, long time ago. I’m pretty sure it was Laos). Before arriving, I bought enough Lao currency for my stay, but the locals only wanted USD. I had to re-exchange my local currency for USD at a pretty bad rate.