Absolutely!
You can reduce your calories by 100 - 200 during the week to give yourself an extra buffer if you know you'll be going to a big event, say a wedding, a BBQ, or a meal out.
But this is only if you want to, if you feel that it will help you relax and enjoy the event that much more.
The other option is to just enjoy the event anyway and then get straight back to it.
I promise you that you won't do as much damage as you think!
What we don't want, is for you to enjoy said event, and then make adjustments afterwards out of feelings of guilt or punishment.