Responding "Maybe" to an event

Is it ok to respond "maybe" to an event even though you know you aren't coming? What about if you that you ARE going? When should and should you not use the "Maybe" response to an event? 
The least you could do if responding "maybe" is to post something on the wall explaining why you can't commit. Otherwise, it makes it look like you're saying that you might come if you have nothing better to do. 
Edit this page and add your thoughts.
==Etiquette==
If someone you know well made the event then it's best to respond 'maybe' only if it really is a maybe. Otherwise you're better off ignoring the invite until you know for sure.
Category:Facebook Etiquette
Category: Events