Consider:
gndlp@ubuntu:~$ test -x examples.desktop && echo $?
gndlp@ubuntu:~$ test -x examples.desktop & echo $?
[1] 2992
0
W
& executes a command in the background, and will return 0 regardless of its status.
From the man page:
If a command is terminated by the control operator &, the shell executes the command in the background in a subshell. The shell does not wait for the command to finish, and the return status is 0. Commands separated by a ; are executed sequentially; the shell waits for each command to terminate in turn. The return status is the exit status of the last command executed.