In my current Germany (Arma 1.3 Beta 2, DAIM) game, custom difficulty (i.e. giving Allies and Cominter a large bonus, while everyone else stay at 100%) neutral Romania refused to cede Bessarabia and instead declared war on SU in mid-1940. Romania has less than 40 divisions, while SU has about 450. Nevertheless Romania has taken a SU province and was able to hold it (it's april 1941 now). SU has not taken any Romanian province.
I did not interfere yet (I neither allied Romania nor attacked SU).
Philipp
I did not interfere yet (I neither allied Romania nor attacked SU).
Philipp