While it is possible, it is not recommended nor suggested by any means (what if you code it to merge the 3rd and 4th arg but you enter a name that has 3 spaces, you will encounter the same thing again). Just stick to the quotes, it will make life much easier. Also, AMXBans does not require quotes on the reason, because it is the last arg and it parses the args manually instead of automatically. It still requires quotes on the SteamID/Name/IP if you are using a space or other delimiter.
I do not browse the forums regularly anymore. If you need me for anything (asking questions or anything else), then PM me (be descriptive in your PM, message containing only a link to a thread will be ignored).