If the purpose of hosting this event was to aggressively sell
Singapore's image to the world, then I think the PR work was not
well done.
Maybe it all started out as a bright marketing idea years back when
the agreement was signed, but the policies that were created
following that conflicted with their objective; there was no
follow-through.
I think the government could have afforded a more lex policy on
civil group entry and demonstrations. Make an effort to create an
assembly that allowed for some peaceful protests and meetings. This
would have been the political and PR coup that they were trying to
achieve.
Now they're doing it the usual way - 100% shut down no exceptions
allowed. While us locals are used to this method and swallow it
without much protest, it won't hold up to global scrutiny.
Of course a peaceful demonstration sounds like the dream scenario
and realistically speaking, we don't live in a perfect world. This
notion might be just wishful thinking, a far-flung ideal. But if
they don't even TRY to achieve this, then what is the purpose of
hosting this meeting?
At the very least, show that you are magnanimously allowing certain
groups in, or allowing certain events to take place. Be creative
and promote what was done, not allow people to highlight what
hasn't been done.
Anyway, the only winner out of this meeting is the IMF/World Bank.
They have their cake and get to eat it too! Finally, a meeting
without the pesky protestors, and they even get to come out of the
event looking like a tree-loving hero - campaigning for the civil
groups' entry- while the S'pore host gets all the blame 
Who says the ideal scenario can never happen? 