According to the Merriam-Weber Dictionary, a "tip" is "a gift or sum of money tendered for service given or anticipated." The tipping etiquette in the event planning world is confusing. I think it is confusing because there is really no general consensus or "rule" on tipping vendors. After researching and talking many, I found these two websites that sum it up the best. Have a look and decided for yourself how you want to tip.
1. From Frugal Bride website, click here.
2. From Martha Stewart Wedding website, click here.
In the end, though, it's all about how good of a job you think your vendor did for you. Did they make your event brilliantly beautiful? Did they help make your day one of your best days ever? The same Merriam-Weber dictionary defines "gratuity" as "something given voluntarily or beyond obligation usually for some service." Thus, your tip is an optional payment to show the vendor your appreciation of their excellent service, if they indeed did give you excellent service - so you decide!