I hear what you are saying that it is rude to charge a cover into your wedding. But the same logic can be applied to flight and hotel. These are necessary costs for the guests to come to your wedding (unless the bride and groom are in a position to pay for it) and thus essentially meet the criteria for a 'cover charge' By having a DW, you are already asking people to shell out money. I just don't necessairly see the difference between passes to the resort or a flight down, unless there is special circumstances.
The way that FI and I look at it is this: we are going to get married in this resort, and this is the cost. We want as many people who can come, to come. We hope to spend the time at the resort celebrating all of our different family bonds or friend bonds. We did not even give an option to stay at another resort. We would completely understand if some of the individuals can't afford the cost and thus can't come (and appreciate them even considering to come). However, if a couple decides they are going to come, but at a cheaper resort - that's fine too, but I think they are the ones who should be calculating into their budget the extra expense of not staying at the resort in making the decision to come.
We are not demanding or even asking people to come. We are simply extending the invitation to join us. If individuals would like to come, but decide they don't want to stay at the same resort as us, and thus effectively not spend the week or time with us - that's fine. But in my opinion, I don't think it is necessairly fair then to ask the bride and groom to pay for their entrance into the resort.
I am not saying in all instances that this approach would work - but that this is the way that we will be approaching it. But also we did not have to consider local guests in the area. We are also lucky in the sense that everyone that we need to have with us - are in a position to afford to stay at the resort. All I'm saying is - that I don't think it is fair to say as a general rule, you Bride A and you Groom A are rude if you don't pay for the passes. It is a matter of circumstance.