The 10-day Vipassana retreats were traditionally created in Burma, to my knowledge that is, I'm not sure. I think it was a Burmese tradition. Usually when the Thai people practice, they don't have limits to the retreat time, and they probably will not keep totally to silence, because it's very difficult in a Wat atmosphere. However during the 3-month rains retreat for monks and nuns, I do know that some of these people do keep to silence quite strictly, they make a personal resolution to do this. Some of the Thai people know what the foreigners are doing and some of them do not. But they all know that you are meditating, they may not know what type of meditation you are doing but I think they all know that you are meditating.