I'm sure all sorts of travel bans were in place for active military personnel, including civilian staffers. Once they're retired though? I mean, we're talking of free democratic systems which in the 80s allowed former flag officers to form a group like "Generals for Peace" to agitate against NATO policy, with a dozen members from various NATO countries like MGs Gert Bastian and Günter Vollmer (GER), MG Johan Christie (NOR), FM Francisco de Costa Gomes (POR), BG Michael Harbottle (UK), LG Georgios Koumanakos (GRC), MG Chiel von Meijenfeldt (NL), and Admirals Militades Papathanassiou (GRC) and Antoine Sanguinetti (FRA). Which turned out post-Cold War to have been inspired, and financed to the tune of 100,000 German Marks annually, by the Stasi and KGB via Darmstadt Technical University teacher Gerhard Kade, a main influence agent for them on the West German peace movement. To the point where their speeches were written in East Berlin.
Not that anybody was in doubt about its background at the time. Others like General Wolf von Baudissin, one of the Bundeswehr's founding fathers, saw the light early on after they tried to drag him in, and Generals Bastian, Meijenfeldt and others attended a screening of a film made about the group by DDR propagandists Walter Heynowski and Gerhard Scheumann in East Berlin in 1986. Bastian for his part suffered no ill effects after resigning from command of 12th Panzer Division and Bundeswehr service in protest over the NATO Double Track Decision in 1980 - joined the Greens, and was elected to the Bundestag in 1983. Some suspected foul play when he shot himself and his girlfriend, Green party and peace movement icon Petra Kelly, in 1992, but no evidence has ever been established; more likely he was just another guy who saw his world break down after the end of the Cold War.