FWIW, Mythbusters tested it.
Episode 33: Killer Brace Position and Cellphones vs Drunk Driving

The brace position on airlines increases chance of death: mythbusted

Talking on a cellphone while driving is as dangerous as drunk driving: confirmed

http://kwc.org/mythbusters/2005/06/mythbusters_killer_brace_posit.html

From the same:

"On July 15 2010, Apple released iOS 3.2.1 (build 7B405) for iPad (first generation). We verified that iOS 3.2.1 does not exhibit this bug."