We recently implemented an auto-close CTA system in GonG (Gainsight's own instance of Gainsight) for our Support Risk CTAs. Wanted to share! We have 3 different types of Support CTAs:
1) New High/Urgent Support Ticket
2) 5+ Tkts Opened in Past Week
3) Tkt open for 21+ Days

Here's our autoclose solution:

3 Custom fields on Customer Info:
-Open Support Cases
-Open Support Cases (High Priority)
-Open Support Cases (21+ Days)

5 Rules that run each day:
1) Load 0's to the Custom Fields above
2) Rule that counts # of open tickets for each account and loads to "Open Support Cases"
3) Rule that counts # of open High Priority tickets for each account and loads to "Open Support Cases (High Priority)"
4) Rule that counts # of open 21+ day tickets for each account and loads to "Open Support Cases (21+ Days)"
5) Rule [built on the Call to Action object] that filters for active, unflagged, rule-generated Support CTAs
   -If Open Support Cases < 3, close Support: Volume CTA
   -If Open Support Cases (High Priority) = 0, close Support: Priority CTA
   -If Open Support Cases (21+ Days) = 0, close Support: Duration CTA