From the ESPN report:

Referee Bill Vinovich, who led the game’s officiating crew, lives in Newport Beach, California. Down judge Patrick Turner, whose primary responsibility was to follow (Tommylee) Lewis on the blown call from start to finish, lives in Lakewood, California, in Los Angeles County.

Side judge Gary Cavaletto, whose job was to initially watch outside receiver Dan Arnold before shifting his focus once the ball was thrown to Lewis, lives in Santa Barbara, California. Back judge Todd Prukop, who was stationed in the end zone as an extra set of eyes on the controversial play, lives in Mission Viejo, California.

As a person who officiated sports at levels up to the college level, at the higher levels referees have litigation insurance. Even at lower levels (youth and lower schools) people get insurance for just such a thing. It’s cheap and well worth the peace of mind.

It would be inconceivable that the referees at the pro level don’t have litigation insurance.

Note that I didn’t say “missed” but rather “ignored”.