Sunscreen should be available not only on match days but at training and practice sessions.
Generally training and practice sessions are undertaken during UV Alert times of the day/afternoon and therefore sunscreen should be present for participants use. There is nothing wrong with carrying a small tube or roll on to be applied throughout the day as it will help.
Recently in Australia, Choice Magazine conducted tests on various SPF 50+ sunscreen products and the results are here
Choice found that only two sunscreens tested reached their Sun Protection Factor (SPF) rating. They were Cancer Council Classic 50+ and Nivea Sun Kid SPF50+ (roll on).
It is recommended that these be used as they provide the best sun protection.