Giving blood is vital and celebrities should be used to promote it. Once every season, football teams should give blood, have a cup of tea and a biscuit, and then play their match.
This. Giving blood is a good thing. But NEVER put anyone in a situation when they might feel pressured to give blood.
(30 years ago, when I worked in an office, on blood donation days I would announce loudly that I have bad veins and had been told not to donate. This was true but the reason I made such a fuss about it was to give cover to other people with possible reasons for not donating.)