What matters is playing football matches unless there's a reason not to do so.
Logically the matches should only be under threat if the majority of the people attending didn't wish to do so out of respect for the Queen or would rather be at home watching the 24 hour news coverage.
I guarantee that if a straw poll of football fans was done that well in to the 90's% of fans would say to go ahead with matches because there simply isn't a strong enough connection between the Queen and football to call them off.
With the way the world is at the moment we shouldn't be looking to cancel more things, people need things to look forward to and enjoy, bringing the country to a standstill won't bring anyone back to life and in a week and a half all that will have been achieved will be more fixture backlog in an already crowded calendar.