Everything in /tmp is removed on reboot by default on some operating systems unless a local systems administrator decides to change that policy. I have no idea what Ubuntu does by default nor what the sysadmins who run your site have decided to implement.
It never hurts anything if you decide to clean up your temporary files when you're done with them! 
I added a line to play a sound file.
The error text file says
VLC is not supposed to be run as root. Sorry.
If you need to use real-time priorities and/or privileged TCP ports
you can use /usr/bin/vlc-wrapper (make sure it is Set-UID root and
cannot be run by non-trusted users first).
#!/bin/bash
#
# located in /lib/systemd/system-sleep/
# Created 4/2/19
exec 2> /tmp/systemd_suspend_test_err.txt
if [ "${1}" = "pre" ]; then
# Do the thing you want before suspend here
echo "we are suspending $(date +%I:%M:%S_%D)."
elif [ "${1}" = "post" ]; then
# Do the thing you want after resume here
echo "and we are back from being suspended $(date +%I:%M:%S_%D)"
# gxmessage works IF xhost + is run first.
gxmessage -timeout 5 -fg red -display :0 'Back from being suspended.'
cvlc /usr/share/sounds/My_Sounds/Relax_6_Seconds.mp3
fi