ATM/Credit Card PINs

Hi two questions I have regarding PINs for ATMs and credit cards:

1) The debit card I have with better fees pertaining to ATM withdrawals has a 6 digit PIN instead of 4 digits? Is this going to be an issue with the Post Bank and 7-11 ATMs?

2) Will it be an issue with PINs for credit cards? I do have PINs but never use them - can I get away with having the merchant swipe my card?

Thanks!