The test results are just in, and you are spot on.
In a carefully controlled experiment, Mrs Berin removed a boot under observation after a rainy ride home tonight. On removing the boot, the sock was confirmed dry.
The other boot was then removed, sock dry, but it was then noted the sock on the first boot was wet!
Looks conclusive that the wet socks were due to wet trousers dripping onto the sock, after removal of boots.
First prize to Vern, for solving the puzzle!
Mrs Berin is now going to email Motolegends with the final analysis.