extends your liability protection (the basic $20,000/$40,000 limits under Bodily Injury to Others) up to the amount you purchase under this part. This option provides coverage for accidents beyond Massachusetts to anywhere in the United States, its territories or possessions, or Canada. This coverage also pays for damages suffered by guests in your auto.
Your automobile is not covered in any country other than the U.S. and Canada.
You could be sued and may be liable for much more than the $20,000 per person and $40,000 per accident limits required under Bodily Injury to Others ( Part 1).
Buying higher limits under the Optional Bodily Injury to Others coverage may make good sense if you have assets you wish to protect.
Source: Massachusetts Department of Insurance