Can the Lifetime sit-on-top kayaks tip over?

The answer is yes, but not easily.  You can tip one over, but you almost have to try.  Leaning to one side will tilt the kayak but you would almost (especially if you are a child) fall out before tipping the kayak.  The 10' kayaks are the most stable as they have the widest width.  However, the others are some of the most stable in the world.  In fact, children can even jump off the side of the 10' kayaks.