I remember saying that the Secret Service has a sophisticated portable toilet for the president to use when he's travelling, but the only source I could find was some conspiracy website. (I found it during the Bush II administration, so it's either gone from the Internet, or Google has probably lost it)
"According to Russian newspaper reports, in the 1940s Stalin's secret police had set up a special department to get its hands on people's faeces.
The ambitious aim: to analyse samples of foreign leaders' stools.
In other words, espionage via excrement."
https://www.bbc.com/news/world-asia-35427926