Charities run these sort of events primarily as fundraising. People who have spent some time volunteering are way more likely to donate and continue donating. I

Charities run these sort of events primarily as fundraising. People who have spent some time volunteering are way more likely to donate and continue donating. It's common that it costs the charity more to supervise the untrained company people than it would to hire for the tasks, but it's still positive when you factor in future funding.