Those of us living in democratic states may not think about this a lot, but there is a strong connection between meetings and the freedom of assembly. As @richard.freeman and others have pointed out, to meet and discuss a common future and to coordinate collective action are inherently political. In the past few days in Hamburg, where the G20 meeting summit is to be held on 7-8 July 2017, we are reminded (once again) that the freedom of assmbly is under threat, even in a democracy like Germany.
Over the past days, protesters have been kept busy challenging police orders in court. First they were denied the use of public space for an international protest camp, when the German Constitutional Court ruled that this violates the constitutional right of freedom of assembly, the police limited the area that could be used for the camp and denied protesters to set up sleeping tents (tents for assemblies were allowed) and prevented the camp from being set up, essentially preventing many international activists from participating in the camp. This police order has so far been confirmed as legal by one court (Oberverwaltungsgericht Hamburg, 4 Bs 142/17).
If you have further information about how this legal battle develops or thoughts on the freedom of assembly more generally, please share them here (in any language).
In the mean time, here is a link to the website of the activists: http://g20-protest.info/