Does viminfo store nested lists?

When I look at the help file for viminfo (7.3.1314), I see this scary sounding passage:

:h 'viminfo

"Nested List and Dict items may not be read back correctly, you end up with a string representation instead."

I justed tested this and it seems that nested lists and dictionaries are read back correctly. What does this scary sounding "may" mean?

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