For Europe, it is Chip and PIN rather than signing
All cards issued in UK (with a few special exceptions) are chipped and have to be used with a PIN
If a card has a chip, the PIN must be used
If it has no chip ( as most cards in Australia are) it can still be used via the stripe and signing. There are places in UK where I have found there are problems with this where the retailer has claimed that they cannot take cards without a chip so I suggest taking a copy of the rules. Also, some machines ( such as some train companies ticket machines ) will not accept cards without a chip
Dave