This forum should be anti-sarcastic.

[FutureNyanCat]

Please, don't use sarcasm at all. It can be very difficult to tell the intended tone of posts on the Internet, so exercise caution when using sarcasm, or don't use it at all. Sarcasm is kinda annoying and won't contribute to the topic. This can cause a person who frequently posts sarcasm to get warned.

Take a look at illias3000's Art Topic. Darkonius64 was becoming too sarcastic there, and thus he was warned.
I recommend everyone to exercise caution when using sarcasm, or don't use sarcasm at all. This is not constructive criticism, and won't help the user at all. Sarcastic jokes should never be allowed here, as this is a forum for SMBX, not sarcasm.

[Karl Marx]

No.

People should post however you like, we're not making it a rule not to be sarcastic. If you can't handle the forum, leave it. We won't cater to your needs

[Shadow Yoshi]

To put this in a lighter way, if users are being disruptive with their sarcasm then they'll be taken care of.

You shouldn't take things on the internet so seriously.