Pressing enter will submit the current written password in the prompt. If the user is using that to wake the screen, probably the password field is empty so you're submiting a wrong password which might lock your account for a while if you have several failed attempts already
You still have lots of restaurants that don't accept cards, mainly outside cities. They say it's due to the cost of renting the card reader & the transaction costs but I think it's so it's easier to not declare the earnings.
Usually bright headlights / highbeams are useful in there.