Hope if that occurs you don't lose that much of a balance...

Plenty of other international callback cards you can use if that occurs.

Not at all. I only have about $9 on it. I was actually going to their website to try to topup, as I had planned to test it out (by forwarding my cingular mobile to it) on a southern caribbean cruise that I will be taking in a couple of months. Yep! I have UM and freeGlobalSim to use if it so happens yackie is no more.

Another thought on inexpensive calling from Bermuda to other countries, the international call back sim Hop Mobile could be used with Callback World or other callback service to trigger a callback. Cost would be the outbound trigger call or SMS plus 35 cents a minute inbound from Hop for the return call plus the callback service cost per minute. Hop is pretty expensive for outbound at 95 cents a minute, so this would likely be the most logical solution with them.
A local sim (Telecom Bermuda or Digicel)and/or local prepaid calling card would likely be the easiest and cheapest, but just a thought on another wireless solution....