Is it possible for someone accused of a felony sex crime in the United
States to escape prosecution by leaving the country before the trial
date and therefore violating the terms of a 100,000 bond?

The person might escape prosecution but then would have an arrest
warrant outstanding. They would have to find a nation that does not
have an extradition treaty with the US and hope that country doesn't
negotiate one. And I don't believe such a warrant expires.

A hundred grand should buy a good enough lawyer to get out of a class
1 or 2 felony sex rap.

I don't believe you can ask a U.S. licensed attorney this question
without creating, in them, the question of whether they have to bring
your interest to the authorities. Very sticky situation. Be very
careful.

This site is an excellent place to get advice from non-lawyers on a
sticky issue like this.

Almost anything is possible, but is it worth the time, trouble, money, etc...

Also, there exists a special class of people called, believe it or
not, bounty hunters. A few years ago, a man in a similar category ran
into Mexico, and this big brute bounty hunter sneaked into Mexico, and
physically dragged him  back to the States. he got arrested by the
Mexican police, but the culprit was back in jail in the States, and
the bounty hunter wasn't in jail very long. I forget his name, but for
$100,000 he can get you anywhere in the world, extradition treaty or
no. That's how he makes his living.

Weiss, attorneys answer questions like this all the time. What they do
is insist the question be a hypothetical question, since they may
indeed be forced to report a serious conspiracy to commit a felony. 
As long as they advise that this is a serious crime to do such a
thing, with all the penalties, they can answer. What they can't do is
help anyone accomplish the goal.

I don't find the question sticky at all.  What he is asking
constitutes a major felony, and the answer as always is this is not a
real good idea.  Nobody needs to be an attorney to tell him this.

To be unable to answer such a question correctly would be akin to
being unable to tell your kid why he shouldn't use drugs or drive
twice the speed limit, which are also crimes.  At the same time, it is
also a major crime to teach someone how to do such things or to help
them do it. The legal term is "conspiracy" and is almost always a
felony in itself.

The fact he/she had to ask tells me he/she won't get away with it.

When I took criminal justice courses in college as electives, I was
surprised to learn that it is totally legal in almost all states for
bail bondsmen or their agents to nab those who jump bail, anywhere in
the US, and toss them in the back of a van and drive them in
conditions illegal for the transport of dogs, back to the bailing
courthouse.  This particular course was taught by a judge.

I dunno, Irlandes, an attorney is an officer of the court and is
expected to report illegal behaviour. If the person in question is
foolish enough to confide illegal activity, that person deserves what
they get.

This is why the attorneys I know talk first in their interviews and
explain things to their clients, hopefully before the client has a
chance to shoot his or her mouth off to anyone. Speaking in
hypotheticals can be sticky, as Randy "Duke" Cunningham found out.