:As it is obvious from all the provided citations despite shaking hands, there was actually no peace achieved. While the story might seem pleasing to one of the sides, I do not see any resolve in it, There are also known border skirmishes with numerous casualities for almost all the 18 years since 1920.
Ruling of the Hague tribunal in 1931, that Lithuania does not have to allow Polish transit through Lithuanian territory, only proved the status quo. I'm not sure, but as much I do remember, Hague ruled this, declaring Poland as aggressor in Vilnius case. To make sure I'll need to check my books. 
Lithuanian government did understand, that after the coup there was small possibility, that Poland would use the coup to justify aggression against Lithuania. It seems Pilsudski did also understand that as a possibility. In his diaries there is a record from 1927: "could  not sleep all night, considered whether to attack Lithuania". Although, as the linked article proves, there was active efforts form Germany and Russia to avoid this.