First off, many designers we have worked with do not have computers that can handle files this large. They can become extremely frustrated when their computers crash constantly while trying to work on large files, and this also causes extremely long save and upload times.
Also regarding the file size, a typical 10' booth file is about 700mb at 100dpi. If you were to work at 300dpi this would cause the file to be about 2100mb (or 2.1GB). The largest file size in Photoshop (as a psd file) is 2GB, so you would then be forced to work on files as “Large Photoshop Documents” (psb files). Also most File Transfer Protocol Systems (FTPs) have a limit of 2GB, meaning you would not be able to send the files to a print shop using them.
Another point is that at 300dpi, your images will need to be 3 times as large to fill the same space as they would at 100dpi. A good way to look at this is for a 10' booth. Many of our customers prefer to have one large image for their entire background on a booth. At 100dpi, this image would need to be 154.72" wide x 88" tall to fill that space and have absolutely no pixelation. This is an extremely large image and would be very hard to produce. At 300dpi, the image would need to be 464.16" wide by 264" tall to fill the same area (because now 300 dots fill each inch of space as opposed to 100 dots), making it even harder to obtain.
Finally, our printing software processes files prior to printing at 1440dpi so, as long as the file does not have any visible pixelation before it is ripped, it will be produced very sharply.
All of these points having been made, it is still possible to create a display at 300dpi. Some sacrifices may have to be made, though, and you may be forced to use vector art as a background or a solid color instead of using a large image.
If you still have some concerns or simply have questions about your artwork, feel free to give us a call to discuss them. We have designers on staff who can answer most of your design-related questions.