I agree, tabitha. The crowd numbers at Hogmanay now have to be carefully numbered - it's now a ticketed event. Tix are free, but first come, first served - due to security concerns and safe transport of people to hospital if need be as well as maintaining easy access for emergency vehicles. There's also only 1 A&E in town, and it's on the city's outskirts. Just last week, the fire brigade was unable to reach a burning tenement b/c of narrow streets with cars parked along them. They had to stop about 50m away from the fire and fight it from there.
In addition, Edinburgh's town centre is very densely populated, especially in summer. Its streets also have networks of narrow, steep alleyways lined with multi-story (some stories under the ground entirely) tenements connecting them. One of these buildings went afire a couple of Christmases ago. It took two days to put b/c it turned out that there were 3 stories under the ground itself which were on fire, too. Special experts specialising in mine fires had to be brought in.
There are only 3 streets in town centre which are straight.
Crowd dispersal in an emergency without appropriate time to plan could be tragic.
The population is heavily reliant on buses to get into town centre, which is still an important work centre and trade centre.
And let's not underestimate the risk presented to outnumbered law enforcement, fire brigade and paramedics if enough security isn't sourced.
I agree with trying out best to eradicate world poverty.
But I prefer to do this by volunteering my time and effort to charitable organisations, not over-running an unsuspecting populace from whom I did not even extend the common courtesy to ask.