What's being said is, there are a lot of factors that need to be considered.
One of the most important factors is the type of antenna being used to transmit the signal to earth. Just like radio stations may use an omni-directional (360 degrees) antenna to broadcast to a wide area, some stations may use a directional to target a certain geographic area, as well as a partial omni-directional antenna, such as some stations on the gulf coast will use at night to broadcast northward with a strong signal, but a weaker signal to the south so that they do not interfere with stations in Mexico. Although satellites generally broadcast to a fairly large section of the earth (like the U.S. mainland), some satellites have some transponders that are broadcasting to a specific location (single state), and if you are not in that location, you will not pick up that transponder, even though you may pick up another transponder on that satellite.
The second issue would be power of each transponder, as well as your distance from it. As you get further away from that satellite that is orbiting about 22,250 miles from earth, the signal will get a little weaker, then when you try to pick it up on the opposite coast, you are even further, then cross the Pacific and the distance increases more; but then your elevation setting will also change and eventually you are pointing your dish through the earth to get the distant satellite which won't work. (The satellites follow the curvature of the earth.)
In both cases, you may be within the primary target area and have no problem. But as you get to the edge of the target area, the signal will decrease, and as stated - light clouds may block the (weak) signal. All of the above is also dependent on if you can draw a straight line from your dish to the satellite without having to go through a building or mountain.
It's very unlikely a satellite company will guarantee a signal on the outside edge of the effective footprint of the satellite signal. However, that doesn't mean some customer service reps wouldn't sell/turn-on the service. Turning on some of the services/programs would be a hit and miss, but most importantly, probably wouldn't be good company practice.
I'm in the middle of the U.S. and do not have any problems picking up all of their satellites. However, some transponders are not pointed to me, so I either pick up a very week signal from them, or in most cases, no signal at all.
Reading all of the terms and conditions and other propaganda, there seems to always be an exclusion for HI, AK, and PR; and I believe it to be based on what the "effective signals" are for each area.