First, many Members of Congress, the Military and the Intelligence Services will talk to foreigners as part of their job. Are you suggesting that no-one who has ever talked to a Russian should ever be in politics?
Second, most of those meetings that Trump officials had with Russians were set up by agencies outside the Trump orbit. In one case they used agents from foreign countries to arrange the meeting. In another, someone who was an FBI helper and informant, was sent to Russia to have a meeting. Then when he came back they pointed the finger and said: "Look, he meets with Russians, he must be a spy!"
The Trump Tower meeting was overseen by Fusion GPS who was digging for dirt on Trump. They arranged the special visas required for the Russian participants and spoke to the Russians both before ans straight after the meeting. If that does not shout "set up" I don't know what does. I wonder if the Russians were "wired"?
So, I would say that a memory-wipe device is not required but rather a way should be found to get all the facts crammed into everyone's memories.