I am not sure that travel insurance would be included in the new mandate. I think that was just for regular coverage. Plus, I believe the insurance exchanges open in October, but coverage will not begin until January 2014, when the law goes into effect. Travel insurance is different, because it covers treatment when you are outside your regular coverage area, like in another country and for specific travel dates. Plus, the OP is not a US citizen or resident, so I am sure it would not apply in that instance.
As to what counts as a preexisting condition, I would think an intestinal obstruction is considered an event, unless your records indicate that you are running around with a state of perpetual partial obstruction (which some of us do). Otherwise anyone who has had prior abdominal surgery would be excluded. From what I've read, even if you have a history of something, if it has been a year (or whatever the specified time) since you were treated for it, it is not preexisting.
Are you talking about travel insurance that covers the cost of your trip if it is cancelled or travel insurance for medical treatment while traveling? I presume they are two different types of coverage.
Jan