I believe students should be allowed to use tables in class to read textbook content. This, of course, is more common in college where students provide their own textbooks and they are generally allowed to have their tablets or laptops. Public schools still waver between real textbooks and e-books, students should follow the norms in these situations, as they are not the ones reponsible for providing the reading material.
Tablets are allowing students to have all of their materials plus access to the internet for half the weight of one book. The age of paper books is dwindling fast. Colleges that ignore the writing on the wall are going to cripple their students who will be handling technology far beyond paper books when they get out of the classroom. There are restrictions that need to be implemented and enforced, but tablets are the future.
I think overall that using technology in the classroom should always be encouraged, while there may be a high initial cost to purchasing a large number of tablets over the long run it will be cheaper and more efficient to do so then to constantly be ordering and replacing textbooks.
Students should not be allowed to use tablets in class to read textbook content. This is because books have been part of our civilized history for a long time and we need to keep them in our academic realms. Computers, tablets, and cell phone already take up enough attention from students' time.