> I would hope that with most people having cell phones nowadays, which gives them the ability to more easily regroup after separation, it should be a priority in cases like this to urge people to not form chains and to devalue staying with their group if it affects the flow of traffic.

While true, the reception at such events is usually non-existent due to the sheer volume of people with devices. Even with a healthy quantity of cellular base stations or wifi access points, there will still be serious issues and connections will be spotty at best.