In the past.... if this happened owners would report that theyd come out to open tailgates (the ones with power lift gates).
I believe I remember someone also had a damaged (paint scratched) tailgate.
For the non self opening- I believe the tailgate popping open- would set off the vehicle alarm.
The cases were related to damaged tailgate switches.
Where water got into the switch and built up corrosion.
Just last week- I replaced the sensor pad in our Equinox. I Noticed the rubber pad had torn and I didnt want water to affect it. So I ordered a new one- and installed it. $12.
2010 FWD LT1-Gold Mist Metallic- seats 8.
Build Date- July 31, 2009-2nd day of Spring Hill 2010 production.
2013 Equinox 3.6L - 88,000
2010 Traverse 3.6L- 153,000
2003 Trailblazer 4.2L- 181,500