For those of you that are interested in packrafting in the GC you might want to watch/join the GCHBA (gchba.org) at Grand_Canyon_Hikers@Yahoogroups.com. They are reorganizing and will have a strong voice on what will be allowed in the Grand Canyon National Park.
For a long time backpackers in the GC have used inflatables to cross the Colorado River. They have used everything from air mattresses to rafts. The first time I did it was with a vinyl raft in 1967. At least one person has died doing it. Recently there has been a increase in backpackers using “packrafts” to go down stretches of the river - this puts them in conflict with the commercial and private rafters. The park service is in the process of developing more stringent rules for the use of the river by backpackers (i.e. distance on the river, sections not allowed, camping areas, etc.). Violation of the rules is a federal offense and can get a stiff fine. In addition if someone is caught they may helicopter them out and they will be charged the cost.