Valve first banned betting website bots in the past few months. This was a reaction to several website scamming their users for millions of dollars over the course of several months / years. When Valve released the list of websites which were being shut down, it didn’t include all the websites. However it did include most of the major websites that were in use at the time.
More recently CSEsports, a website which specialises in skin betting has got their bots banned by Valve. A letter released by the website reads as :
Valve has blocked bots from our website for admission/transfer items (Trade Ban). Accordingly, at the moment there is no possibility to enter or withdraw items on our website.
We don’t accept any warnings or alerts. Also we failed to achieve any concrete explanation of the situation from the technical Steam support.
Below is a screenshot of communication with technical support from the account of one of our bots.
They have assured their users that they can bet using the skins on their website. However withdrawals can not be implemented right now due to the trade bans received by Valve.