In all my reading I have found that people have a very conflicted relationship with the convention host hotels. We demand everything from them, and begrudge the cost such demands require.
Make a Budget
Hotel rooms cost money, get over it. I understand that not everyone has the same income, and splitting a room 8 ways, or staying in a cheaper place down the road is unavoidable for some. If that is what it takes to get you there, so be it. However conventions typically get good rates for their members so griping about the price is ultimately pointless and not very classy.
Not getting a hotel room and trying to camp out in the video room or bathroom is really not a responsible option unless you are attending Hobocon. Shitty behaviour like this can ruin a convention's reputation with a hotel.
Room and food costs at the hotel are the biggest portion of a convention budget, even including airfare. Recognize this before the convention and make a budget you can live with. I'm always amazed when people scramble a month before a convention trying to make last minute cash, especially when the event occurs yearly. A little planing will make for a less stressful event. I have a spread sheet for each convention I go to, that basically does this:
Room rate x number of nights / number of people = Room Cost
Food per Diem x number of days = Food Cost
Room Cost + Food Cost + Membership + Spending allowance + Airfare = Total cost
Total Cost / 12 = Amount you need to save per month to afford the convention.
Some numbers are fixed like the room rate and airfare, buy adjusting the food costs and spending allowance I can make the final cost something I can work with. It is easier to save a little every paycheck for a big event than it is to scrounge a bunch of cash together in a month.
Respect the amenities
Anytime you are on vacation, you should treat the hotel as part of the trip. At conventions there are constant panels and parties that are the real reason for attending, making your room not much more than a pit stop for the weekend. However, you will enjoy the experience more, and grouse the cost less, if you take in at least one hotel activity during your stay.
These hotels hire good chefs for their restaurants, so treat yourself to one high-end meal. Or go to the pool, get a massage, or treat yourself room service. Not every day, obviously, but doing one fun "away from home" activity will make your trip more enjoyable. It is a shame to stay in a four star hotel, eating nothing but ichiban out of a coffee pot.
Also, eating at the hotel really helps out the convention. The total cost to the convention organizers is dependant on how many rooms the event fills, and how much food and drink revenue the event generates.
Finally, Remember the rules apply there too
Many treat the convention space as a private compound, where the laws of man and God have no meaning. Destruction of property, public nudity, wielding weapons, non-consensual groping are not appropriate at a convention, or anywhere else. I think this is part of the chaotic neutral world we live in, where each values his own liberty but doesn't strive to protect others' freedom.