There are two separate issues as well, whether or not a restriction is valid and the ease with which it is circumvented. Lots of EULA/TOS terms are unreasonably broad. But let's say the TOS says "use of service without a password is unauthorized". Seems reasonable.
Somebody runs a program to guess passwords until they find one that works. "Ah ha," they say, "I have a password, so my usage is now authorized." I don't think a judge or jury will buy that. Even if the password was easy to guess.
I believe that was SpikeGronim's point. Assuming the definition of unauthorized is legit, there's no such "it was too easy" defense. Or "I could do it, therefore I must have been allowed to do it."
