Answer:
Public celebrations allow people to be merry and happy.
Because there are usually large crowds, there is a tendency for questionable characters to blend in. Many of them use the crowd itself as cover for their nefarious activities such as pick-pocketing, breaking into shops, and several other activities.
One of the simplest ways of stifling these sort of activities is through the use of technology. With high pixel security cameras, it is easy to perform facial recognition on people who are caught. When people come to this realisation, it probable will slow them down if not stop them completely.
High definition security cameras are already in use in countries like Honk Kong.
Another way it can be overcome is to have a lot of police presence.
Lastly, when people commit such crimes, they should be made to pay for it dearly.
Cheers!