Yes you are correct, its entirely possible that it isn't deliberately neglected. However, like you said it wouldn't be all that difficult to set up and it might improve customer relations.
Just for arguments sake here is the info about the legality of listing the GST
Always disclose all components of the price, including extras such as GST or other taxes
Businesses should disclose all components of the price when displaying, quoting or advertising prices. The price you see should not be subject to additional or ongoing costs unless these are clearly specified. If a product or service is subject to GST, then the prices displayed or quotes obtained must include GST.
If you are unsure about what is included in the price of a good or service, check with the business or ask for it in writing. Make sure you read the fine print of advertisements or contracts before you make your purchase. [/quote] http://www.accc.gov.au/content/index.phtml/itemId/815334GST & online shopping
Whether you buy in a shop or online, you have the right to know how much you will be charged for goods or services.
By law, Australian businesses selling to consumers are required to display prices that include, or clearly show, the Goods and Services Tax (GST) component.
Because many Australian businesses use the internet to sell goods and services to overseas consumers (who do not have to pay GST), the rules they follow will depend on who they are selling to. If you understand the rules that businesses follow when listing prices on their websites, then you will know what to expect.
Selling to international and Australian consumers
These sites can display a price that does not include GST for the benefit of consumers outside Australia. However, they must also display the GST-inclusive price for Australian residents.
Selling to other businesses
If a business has been listing GST-exclusive prices for other business customers, it can continue to do so, as long as the site clearly states that GST has not been included.
Selling only to international consumers
A business that only sells goods to overseas customers can display GST-exclusive prices on its website. It should be clear that the price does not include the tax component so any potential domestic consumers are not misled.http://www.accc.gov.au/content/index.phtml/itemId/255377
Once again, does anyone know who we can send an email or send a message to see what needs to be done to remove little bird electronics from the distributors webpage. Would it be appropriate to email team@arduino.cc with regards to this matter?