Copter: refuse to enter manual throttle modes while landed with throttle high

ArduCopter/control_acro.cpp

@@ -9,8 +9,11 @@
 // acro_init - initialise acro controller
 bool Copter::acro_init(bool ignore_checks)
 {
-    // always successfully enter acro
-    return true;
+   // if landed and the mode we're switching from does not have manual throttle and the throttle stick is too high
+   if (motors.armed() && ap.land_complete && !mode_has_manual_throttle(control_mode) && (g.rc_3.control_in > get_non_takeoff_throttle())) {
+       return false;
+   }
+   return true;
 }
 
 // acro_run - runs the acro controller

ArduCopter/control_stabilize.cpp

@@ -9,11 +9,13 @@
 // stabilize_init - initialise stabilize controller
 bool Copter::stabilize_init(bool ignore_checks)
 {
+    // if landed and the mode we're switching from does not have manual throttle and the throttle stick is too high
+    if (motors.armed() && ap.land_complete && !mode_has_manual_throttle(control_mode) && (g.rc_3.control_in > get_non_takeoff_throttle())) {
+        return false;
+    }
     // set target altitude to zero for reporting
-    // To-Do: make pos controller aware when it's active/inactive so it can always report the altitude error?
     pos_control.set_alt_target(0);
 
-    // stabilize should never be made to fail
     return true;
 }