haha so true. especially if the restaurant / shop is small one...
for chain restaurant/shop mostly accept any amount.
some restaurant accept minimum rm20, rm50 before can use credit card..
some shop accept minimum rm100 or rm250 before can use credit card..

so the best way, if you carry rm5 and want to eat fancy lunch / dinner ask the waiter if can use card (mastercard/visa/amex/debit) and the minimum amount they accept. also there is other variable like the machine faulty la, cannot connect la, cannot read chip etc...