its an inidividual choice, those risks have different conseqences for everyone, I cancelled my 4 day trip to the UK this weekend. Had I been viisiting the Uk for a month then I probably would not have ciancelled.
where the tipping point would have been (5 day trip, 10 day trip...) I am not sure.
Based on the pilots union/easyjet looking for compensation then I suspect many people are cancelling.