you seem to have misunderstood what i wrote, let me make it really clear for you - the end part where i say "seems completely reasonable" refers to the words just prior to it. the words right before it are "they (the police) put out the message all day that gathering would not be allowed at night" and the fact that they have been pushing the crowd into a smaller and smaller area all day, making it appear larger as you pointed out.
maybe if i rearrange the words and incorporate your context it will become clear;
the crowd seems to be getting bigger, it is because the police are corralling the people into a smaller and smaller area, i find this action by the police completely reasonable because the crowd and mood will change at night and because they warned people all day that gathering would not be allowed after nightfall.
let me know if you need any further clarification.
BBM
I just watched a clip of a presser by the Ferguson Chief of Police on MSNBC (via cable, so no link). When asked, he specifically stated that there was no official curfew in effect. IOW - martial law has not been implemented in Ferguson. I didn't hear him say anything about protesters not being "allowed" to assemble at night. He was saying that protesters were being asked to not protest at night for their own safety.
There's a big difference between "not being allowed" and "being asked".
Legally speaking, unless the mayor implements martial law and sets a curfew, protesters cannot be prohibited from peacefully assembling either day or night. Peaceful assembly is a 1st amendment right.
Law enforcement has the duty to respond to violence or threats of violence, vandalism, etc. We have to bear in mind that the strong police presence we're now seeing in Ferguson is a direct consequence of the violence, looting, property damage, arson, and vandalism that occurred over the weekend.
I oppose any police action that unjustly targets nonviolent protesters, reporters, or bystanders. This is already an extremely volatile situation that will only escalate if the officers on the ground don't keep their cools. The thugs responsible for the weekend mayhem are looking for an excuse to wreak more havoc, and it will be the peaceful folks who'll suffer because the unnecessary violence detracts from their message. The cops need to be careful in how they respond to the law-abiding demonstrators. At the same time, the peaceful protesters need to continue to be respectful, as well as recognize that the thuggery that occurred over this past weekend is the reason why the SWAT teams are out in full force.