Quote from DD2. Please put a warning in the server title if you use bots!!! I don't mind playing with bots when they're less than 50% of the server. If I get a warning I can check the server info and investigate how many bots are on the server, if I don't get a warning I often end up waiting for a massive CSS load time which is even long on my effing fast computer before having to cancel and find a new server.
Not sure if it's been said, but one of the most hidden secrets of the steam server menu is being able to see instantly which servers have bots on. Want to know how? Right click on the top bar of the server list (where it says servers, latency, map etc), and you should see a list appear. Tick the option 'Bots'. This will add a small field to the left of "server" with a B in it. Now any servers with a yellow square and a B inside it to the left of their server name have at least one bot in them. Simple!