Parking around Unibet arena

Hi
I don’t usually use a car around Tallinn but in this case need to and am trying to understand the parking situation. Event parking is almost 30€. There’s some paid lots around the arena but the arena itself mentioned that the mall parking lot is really near. And from what I find it’s free. Would there be a problem parking there around 6pm and not leaving until like midnight? I know in some countries using the parking lot after closing can get you towed or fined. I’d like to find a free parking option or cheapest that’s safe to walk to.