Updated SC2086 (markdown)

SC2086.md

@@ -83,6 +83,15 @@ This is better than an unquoted value because the alternative value can be prope
 
 ---
 
+Here are two common cases where this warning seems unnecessary but may still be beneficial:
+
+```
+cmd <<< $var         # Requires quoting on Bash 3 (but not 4+)
+: ${var=default}     # Should be quoted to avoid DoS when `var='*/*/*/*/*/*`
+```
+
+---
+
 As always, this warning can be [[ignore]]d on a case-by-case basis.
 
 this is especially relevant when BASH many not be available for the array work around.