I always try to provide both a why behind the rule as well as an alternative.
Some of my rules are:
1.) No red wine - because is stains when it spills. I also add that I'm a red wine fan so this definitely hurts me (who's not drinking anyway) more than you. Alternative: it's summer, and what's nicer than a chilled white out of the cooler on a hot day anyway.
2.) No spray sunscreen - because only about 20% of it will actually hit you and the other 80% will land on the boat and make that part slippery and a safety hazard whenever the boat rocks. As an alternative, we always buy a Costco pack of non-spray sunscreen and keep several tubes on the boat.
3.) When doing any water sports with a rope, the rope MUST not get under the boat. This boat is basically two huge water vacuums under the boat will get sucked in and wound around the propeller shafts. At that point, all the fun gets to stop for 90 minutes while you get to hear me cuss you name as I cut YOUR now worthless $80 tow rope out of the engine.
4.) No shoes on the boat unless you pay monthly expenses on it or worked as a boat mechanic your entire working career (this is for my 83 year old step-dad who was a boat mechanic). Please deposit your shoes in the Shoe bin. Another thing I learned last year at Shasta is to be aware of where and how people are getting to the boat. We had to walk down a red-dirt path across the dry lakebed last year to get to the dock. People were really good about taking their shoes off however, there was still red-dirt all over the boat that I was wiping up. After about 2-3 trips down to the boat, I realized that those who wore sandals or flip-flops got that dust on their feet and once their feet got wet, there was the dirt. I then asked them to rinse their feet in the lake before getting on the boat and the problem stopped.
5.) Beer and wine bottles are generally OK as they take a lot to break. Please throw your bottle caps into the garbage so people don't step on them. Please do not throw them into the soft sided cooler, as they can cause it to leak (yes, I had that happen).
6.) Food, chips, mayo and such are generally allowed. I'm lucky in that people I go out with aren't a Dorito or Cheeto fan, so those aren't around.
7.) As we are cruising about the lake, please try to distribute yourselves evenly from side-to-side. This will help balance the boat and make it more comfortable for all of us. If there is a lot of weight in the boat, I may also ask a few of you to sit up front...this is for performance reasons.
8.) I'm the captain and if I make a request, please respect it. If you don't understand why, you're always allowed to ask to help you understand better. Note though that it may take me a few minutes to get back to you as I may be concentrating on something else at the moment.
I've found that most people are good once they know why I have a rule and what the alternative is...