Sorry, neglected to include important details.

Approximately one week a month on-site at client(s) location. So, flights, food, accommodation.

I expected company payment card. If everything turns to shit one month the employee, in this sort of situation, could be left holding a fairly hefty bag.

In my experience, the norm is minor expenses are, well, expensed. Dinner, taxis, whatever. The big ones that require planning, sometimes HR just take care of - i.e. booking your flights and hotel for you. That being said it isn't unheard of for that to be something you "expense" as well. If they fuck you, sue them. They probably won't though.

Side note: if you're in a situation where you're loading up a credit card with business expenses that are later reimbursed, you may consider looking into a credit card that offers rewards like airline miles. It's essentially a "free reward no fee ATM." I always volunteer to grab the company lunch tab for this reason.