This one is rarely asked and advised: you can't lend to someone else your credit/debit card.
Here in the Philippines, all credit/debit card use are checked. If the name on the card is suspiciously not the customer's name (for example, it's a man's name, but the one holding is a woman), it will be questioned and held.
For credit cards (not debit cards), signatures are also required. If the signature did not match the one on the back of the card, the card will be held by the store.
The only exemption to the rule is if it is a company credit card. As long as you can show a company ID, it will be allowed. This is especially true if the company card is Black, because there are no Black credit cards in the Philippines (at least, I haven't seen one; I've only seen it from Korean and Japanese partners).
There were many incidents of foreigners getting stuck because of lending their cards to a friend or relative. One such was in a supermarket.
