Theres a couple things here I'd like to point out... The 3 main reasons that we may roll and tip a boat are
1 - wind... Being that I'm talking about 40', 50' boats, it's a rarity we can put them inside (tho my new job has a huge building dedicated to this, thankfully..) For anyone who's sprayed outside in the wind, it can be difficult, but not impossible. I have sprayed boats in 20 mph winds, you just need to change up your gun technique, etc.
2 - masking.... You can imagine the time and materials it takes to cover huge sections of boat with paper or masking film. Throw some of that wind in, and it can become quite hectic..
3 - cost vs quality... Believe it or not, boaters are cheap usually.

When rolling and tipping, you can vary the quality greatly depending on how much time you spend with between coat sanding, etc... Many customers are willing to live with a brush stroke here and there.. Which is where i guess alot of you are coming from.
Which brings me to one of the most important reasons to me why I'd rather spray any car/truck over a roll/tip. For the amount of extra labor it takes to get a decent job, I'd rather work, take that money and invest in a $100 gun and some better material...
Some people don't prescribe to that theory.. My old roomate would sit in his room for hrs on end working on projects that he could buy for $20.. I understand the whole "my labor is free" theory and believe me, I use it on occasion. When I did my bodylift and knew I would have the truck layed up for a couple weeks, I spent countless hrs down there scrubbing and stripping my frame down so i could zinc it, epoxy it, and put black Imron on it... Tons of labor for something most would not consider doing.
the other point to this is, not only is it 5x's the labor, consider what kind of labor.. How many of you have wetsanded till you have no fingerprints with blood coming out of the tips? Not exactly something fun.. Good work if your considering bank robbery tho!

Just keep in mind thats what this process entails, tho experts can minimize this by knowing what they can get away with and dry DA sanding certain portions of the job..
For anyone considering this, word to the wise, do not just buy any foam rollers from the Depot, they will fail miserably with any oil based paint. Rollers designed for epoxy use are a nescessity, West Systems rollers are designed for this and what we use..