I got myself a M5-481TG 2 days ago because I was a little bit pissed off of AMDs support for switchable graphics on laptops,
somehow I trust a community driven hack like Bumblebee more than AMD (and OMG that thing works nicely!!).
The trackpad being disabled after every reboot was a bit annoying, so I dug around the interwebs and found out that the acer_wmi kernel module is known to disable touchpads on init.
So, the quick fix for this was:
Luckily, on the M5-481TG the function keys for brightness, volume etc are managed by the hardware.
echo "blacklist acer_wmi" | sudo tee /etc/modprobe.d/acer-wmi.conf
Disabling the touchpad also still works, but with acer_wmi disabled there's no notification shown when toggling it.