question about RUN-PROGRAM

The DOCSTRING for RUN-PROGRAM says

Run program specified by COMMAND, either a list of strings specifying a program and list of arguments, or a string specifying a shell command (/bin/sh on Unix, CMD.EXE on Windows); _synchronously_ process its output as specified and return the processing results when the program and its output processing are complete.

So shouldn't RUN-PROGRAM always pass :WAIT T to %RUN-PROGRAM?

A colleague of mine anecdotally reported that he wasn't getting output from a call to RUN-PROGRAM until he caught and printed the return value.

This is on ALLEGRO, where RUN-PROGRAM invokes EXCL:RUN-SHELL-COMMAND and, I believe, should always be using WAIT, no?

Thanks, r