I like how you make it sound sinister.
The juice is actually coming from inside the strawberries. It's osmosis!
Here's what I found:
The sugar begins to dissolve in whatever water is on or near the surface of the
strawberries. This concentrated sugar solution is then diluted by moisture diffusing
out of the strawberries and into the sugar solution. Gradually, the strawberry tissue
is depleted of water as the solution outside becomes more dilute. Depending on the
amount of sugar added and the water-content of the strawberries, the result is a very
sweet juice (syrup) surrounding the pieces of strawberry.
If you look closely at the strawberries after they have rested in the solution, you will
note that the pieces have become rather shriveled and soft because their internal
moisture has been depleted. This is most apparent in store-bought containers of
pre-sweetened frozen strawberries. Their residence time in the syrup is so long that
the strawberries are almost transformed into a formless mush.