We're planning to run a simple competition at an event. It's a skill based competition (not a lottery), where the best score at the end of the event will receive an android tablet. No purchase is required to enter. It's just meant to be fun. The target audience of the event is very broad, and we expect a lot of children to attend. The event will be in held in Finland and we're a Finnish company.
To run the competition, we obviously need a way to contact the prize winners. It's a two day event, so we are planning to keep an encrypted Excel sheet on a local computer with the player's name, contact information, and score. The only purpose of the sheet is to contact the winner and ship the prize to them - we will securely delete all the data after the event.
(We will get our real lawyer to check our terms and conditions are watertight beforehand, but I don't want to seek their advice if what we're trying to do is clearly illegal.)
In summary, the question is : is it legal to collect contact information on minors to facilitate a "for fun" competition with all data used strictly only for that purpose?