I'm sure a bunch of 99 cent apps will be the least of your families' worries if you were to die.
As would an iPhone! But there is more than 99 cent apps at stake. Consider also any music, video, ebooks or Mac apps (generally much higher priced) you may have purchased.
Pure speculation, but I'd expect Apple has policies in place where the executor of your estate (with appropriate documentation such as death certificate and letters testamentary) can gain control of your AppleID.
Yes, the policy in place is it is non-transferrable!
I found a good reference to legal issues of any Music/Video/Apps purchased from Apple. http://www.digitalpassing.com/2012/09/04/apple-itunes-music-videos-ebooks-die/