The besotted Commander from "The Enterprise Incident" was likely executed for allowing Kirk and Spock to make away with the cloaking device.
She doesn't strike me as the type who would allow that to happen. She'd find some way to skate on any charges the Romulan government might try to levy against her. Especially if she had powerful friends or family.
(Iindeed, in the current novelverse, I think there's one bit where she escapes just such an execution because she is a blood relative of the Emperor.)