Add a little more explanation.

openmmapi/include/openmm/AndersenThermostat.h

@@ -116,7 +116,8 @@ public:
      * results on successive runs, even if those runs were initialized identically.
      *
      * If seed is set to 0 (which is the default value assigned), a new seed is generated from the system
-     * clock when a Context is created from this Force.
+     * clock when a Context is created from this Force. This is done to ensure that each Context receives
+     * unique random seeds without you needing to set them explicitly.
      */
     void setRandomNumberSeed(int seed) {
         randomNumberSeed = seed;

openmmapi/include/openmm/BrownianIntegrator.h

@@ -101,7 +101,8 @@ public:
      * results on successive runs, even if those runs were initialized identically.
      *
      * If seed is set to 0 (which is the default value assigned), a new seed is generated from the system
-     * clock when a Context is created from this Force.
+     * clock when a Context is created from this Force. This is done to ensure that each Context receives
+     * unique random seeds without you needing to set them explicitly.
      */
     void setRandomNumberSeed(int seed) {
         randomNumberSeed = seed;

openmmapi/include/openmm/CustomIntegrator.h

@@ -446,7 +446,8 @@ public:
      * results on successive runs, even if those runs were initialized identically.
      *
      * If seed is set to 0 (which is the default value assigned), a new seed is generated from the system
-     * clock when a Context is created from this Force.
+     * clock when a Context is created from this Force. This is done to ensure that each Context receives
+     * unique random seeds without you needing to set them explicitly.
      */
     void setRandomNumberSeed(int seed) {
         randomNumberSeed = seed;

openmmapi/include/openmm/LangevinIntegrator.h

@@ -101,7 +101,8 @@ public:
      * results on successive runs, even if those runs were initialized identically.
      *
      * If seed is set to 0 (which is the default value assigned), a new seed is generated from the system
-     * clock when a Context is created from this Force.
+     * clock when a Context is created from this Force. This is done to ensure that each Context receives
+     * unique random seeds without you needing to set them explicitly.
      */
     void setRandomNumberSeed(int seed) {
         randomNumberSeed = seed;

openmmapi/include/openmm/MonteCarloAnisotropicBarostat.h

@@ -169,7 +169,8 @@ public:
      * results on successive runs, even if those runs were initialized identically.
      *
      * If seed is set to 0 (which is the default value assigned), a new seed is generated from the system
-     * clock when a Context is created from this Force.
+     * clock when a Context is created from this Force. This is done to ensure that each Context receives
+     * unique random seeds without you needing to set them explicitly.
      */
     void setRandomNumberSeed(int seed) {
         randomNumberSeed = seed;

openmmapi/include/openmm/MonteCarloBarostat.h

@@ -125,7 +125,8 @@ public:
      * results on successive runs, even if those runs were initialized identically.
      *
      * If seed is set to 0 (which is the default value assigned), a new seed is generated from the system
-     * clock when a Context is created from this Force.
+     * clock when a Context is created from this Force. This is done to ensure that each Context receives
+     * unique random seeds without you needing to set them explicitly.
      */
     void setRandomNumberSeed(int seed) {
         randomNumberSeed = seed;

openmmapi/include/openmm/MonteCarloMembraneBarostat.h

@@ -222,7 +222,8 @@ public:
      * results on successive runs, even if those runs were initialized identically.
      *
      * If seed is set to 0 (which is the default value assigned), a new seed is generated from the system
-     * clock when a Context is created from this Force.
+     * clock when a Context is created from this Force. This is done to ensure that each Context receives
+     * unique random seeds without you needing to set them explicitly.
      */
     void setRandomNumberSeed(int seed) {
         randomNumberSeed = seed;

openmmapi/include/openmm/VariableLangevinIntegrator.h

@@ -123,7 +123,8 @@ public:
      * results on successive runs, even if those runs were initialized identically.
      *
      * If seed is set to 0 (which is the default value assigned), a new seed is generated from the system
-     * clock when a Context is created from this Force.
+     * clock when a Context is created from this Force. This is done to ensure that each Context receives
+     * unique random seeds without you needing to set them explicitly.
      */
     void setRandomNumberSeed(int seed) {
         randomNumberSeed = seed;