Definitely do not charge – use it all the time for that reason.
Only thing is the machine at the mini Tesco on Soi Siam country club in Pattaya – eats your bloody card (OK its slightly bent) and you have to go to big Tescos at Nua to plead for it back before they send it to your bank (twice in a week but that was a couple of months ago – no prob since)
Andy