Hi,
My (Thai/Australian) wife just translated the first sign as "no members of the public allowed inside".. well at first she also said "no outside people allowed in" as the literal translation, but it's meaing is along the lines of no random members of the public, i.e. this is a private space.

On that note we did cop some discrimination trying to find rooms to stay on Khao Sarn rd in the past.. now we stay elsewhere in Bangkok away from the backpacker ghettos.

Interestingly the author of the article (Neil Jenman) in question is in Australia and has invited Castran Gilbert to sue him so he can expand on the matter in court and defend himself with the facts. They have not. Instead they went for a third party.

For further info:
http://australianrealestateblog.com.au/blogs/australian_real_estate_blog/archive/2008/02/09/jenman-taunts-estate-agents-to-sue.aspx

Newspaper coverage:
http://www.theage.com.au/articles/2008/02/08/1202234169474.html

The article itself:
http://www.jenmangroup.com.au/news_item.php?id=368