the issue with
trip insurance is there are very detailed clauses regarding preexisting conditions-so even if a person has had no indication of of say an ear infection but the doctors checks the ears as a precautionary measure relative to a minor sinus issue-the trip insurance can and likely will deny coverage.
as far as personal med insurance goes-i would advise anyone traveling outside their 'provider area' to read thier policy in detail. i have some of the best the market offers, but it precludes anything out of my home area unless THEY DEEM (NOT I, NOT THE PROVIDER HOSPITAL) that the issue is LIFE THREATENEING. i was never so glad to have
travel insurance as when both kids came down, day 2 with raging ear infections that required medical treatment. we opted to go with the in room doctors wdw referrd us to (not sure if they are still available-were'nt a few years ago) who prescribed antibiotics and pain relieving drops, and actualy did multiple phone follow ups

-all of which we paid full price for (around $500 total). although the md's and our pediatrician upon our return documented that both kids had they gone untreated would likely have experienced ruptured eardrums on the return flight had they not received timely medical intervention-our insurance company deemed that loss of hearing is not life threatening (god love these people and their empathy

). so our travel insurance picked everything up with a total $50 co-pay.
after that experience i have always budgeted travel insurance in any trips out of state/country-and my pediatricin realy supported my decision back in may '05. my dd (10 at the time) fell, at home, rideing her bike and among other injuries was thought to have simply spained her arm-well, a subsequent xray found that there was a break and at some point during her childhood an bone aneurism occured in her upper arm (humerus) (not as uncommon an occurance as you would pray/believe) resulting in decreased bone growth such that her humerus looked like a soda straw (thin outside layer-hollow inside). luckily we were at home-but still now, 15 months later the bills have topped (thankfully covered by insurance) over $80,000.00-and we have twice annual checkups until she reaches the end of puberty. my pediatrician advised me that she had encountered at least 2 inuries of the same sort-only they occured when families were on vacations (one in hawiii with a child 'boogie boarding', one with a child in the sierra's 'snowboarding")-because both were 'out of network, out of state'-the parent sans travel insurance obligated themselves to tens of thosands in 'stop gap' treatment to stabalize the injuries such that they could return their children home in order to be covered/treated by their private med insurance (again-apparantly potential amputation is not life threatening according to most carriers).
so for us apparnt health-and travel insurance are a must in considering any vacation. if nothing else-when we travel to wdw, we reccognize that there are viruses and such that locals may have developed an immunity to and hvae no symptoms that would concern them about interacting with the public-but for us it may be a new strain we've developed no tolerance to and may experience long term issues with.