Colonel Milfoil claims that it's impossible to contact the Tanners because "I'm afraid they don't have a phone yet, sir, it's hard to get service in Reykjavik." Except this is nonsense — Rekjavik is a modern city and the movie takes place in 1996. Getting a phone would not have been so hard that the Tanners would still be without one after six years. So why would Colonel Milfoil serve such a blatant lie? Because he doesn't want the commitee to contact the Tanners. He wants to present ALF as a dangerous menace who kept the Tanners hostage for years, but he knows the Tanners wouldn't back him up on that. So he just pretends they're impossible to get ahold of and dismisses any questions as "classified."
