From what I have read, there seems to be a strong chance that the recent mishap in the Gulf followed an unintended close encounter with some jetty structure - i.e. barely submerged rocks. Not much info coming out now.
The incident in the Chesapeake Bay was not this winter, but last winter. It was caused by a broken livewell pump WITH AN OPEN SEACOCK. In fact, the owner - like far too many others - was NOT in the habit of closing his seacocks. A hard way to learn a basic lesson that everyone should follow, SEACOCKS SHOULD BE CLOSED WHEN NOT IN USE.
The scoop on the sea water inlet for the livewell, or raw water, will deliver a LOT of water into the boat when running at speed. The natural reaction once you feel the sluggishness is to slow down, and then all that water follows the 'free communication' principle and suddenly moves from aft to forward, and the boat plows and rolls. The usual result is capsize.
I taught small boat seamanship and offshore sailing for a long time. The seacock rule is really a vital step in staying safe at sea.
Another factor this time of year can be trailered boats that collected water inside hoses above closed seacocks, or clogged scupper drains, then have that water freeze in cold weather. This will frequently crack the seacock or scupper overboard fitting, with a great potential for a unpleasant day the next time you launch the boat. I say trailered, but it can also happen to boats on the hard for winter that are not covered, or weren't fully drained even if covered. So, please be aware of these risks and make it a habit to check thru-hulls for structural integrity and to keep seacocks closed unless actually in use.
In case you are curious, our Islander stays in the water all the time, so we have no risk of freezing those connections that are in the water - the water never gets cold enough. Those hoses/connections that are in the bilge, but not submerged (e.g. aft scuppers, livewell and fishbox drains) need to be kept clear of standing water if the bilge temp is likely to get really cold - but that rarely happens here in the great Tidewater area.