The documentation for command line arguments to MzScheme says:
-p ‹file› ‹u› ‹path› : requires (planet "‹file›" "‹user›" "‹pkg›")
http://docs.plt-scheme.org/reference/running-sa.html#(part._mz-cmdline)
Running mzscheme --help says:
-p <package> : Like -e '(require (planet "<package>")'
Experiments confirm the executable is correct and the docs are wrong.
I've committed a change to fix the docs (startup.scrbl):
@it...@flagfirst{p} @nonterm{package} :
@scheme[require]s @scheme[(planet @#,nontermstr{package})].
N.
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