The bottom few inches of the shell (below the floor attachment) on a Scamp
is more of an apron covering the frame. It seems an unlikely place to get a spreading stress fracture, and a more likely place for impact damage.
Mine came with a 6" horizontal crack in the lower front apron (in the photo that's the tongue at the right). Most likely the PO caught the tip of a log or rock in a campsite and bent the apron enough to crack the gel coat and expose glass fibers. It did not separate the fibers and is below the level of the floor attachment, so I consider it cosmetic. It hasn't changed in three years and many miles of towing, so I don't plan to do anything about it.
Stress cracks are more common around windows
, vents, and doors. If the glass is completely separated and the crack appears to be spreading (wider at one end), then it is a cause for concern, especially around the door, which is the weakest area of the shell. Here's an example:
Personally, I'd at least take a look at the trailer and take some photos of the damage. Post them and see what folks think.