diff --git a/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/Command.java b/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/Command.java
index ea7e686f066..473d2723271 100644
--- a/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/Command.java
+++ b/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/Command.java
@@ -29,7 +29,7 @@
  */
 public abstract class Command implements Sendable {
   /** Requirements set. */
-  protected Set<Subsystem> m_requirements = new HashSet<>();
+  private final Set<Subsystem> m_requirements = new HashSet<>();
 
   /** Default constructor. */
   @SuppressWarnings("this-escape")
diff --git a/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelCommandGroup.java b/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelCommandGroup.java
index cb5dcf0c0e2..14d93b6961c 100644
--- a/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelCommandGroup.java
+++ b/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelCommandGroup.java
@@ -50,7 +50,7 @@ public final void addCommands(Command... commands) {
     CommandScheduler.getInstance().registerComposedCommands(commands);
 
     for (Command command : commands) {
-      if (!Collections.disjoint(command.getRequirements(), m_requirements)) {
+      if (!Collections.disjoint(command.getRequirements(), getRequirements())) {
         throw new IllegalArgumentException(
             "Multiple commands in a parallel composition cannot require the same subsystems");
       }
diff --git a/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelDeadlineGroup.java b/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelDeadlineGroup.java
index fae0542322a..86417f27b9c 100644
--- a/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelDeadlineGroup.java
+++ b/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelDeadlineGroup.java
@@ -80,7 +80,7 @@ public final void addCommands(Command... commands) {
     CommandScheduler.getInstance().registerComposedCommands(commands);
 
     for (Command command : commands) {
-      if (!Collections.disjoint(command.getRequirements(), m_requirements)) {
+      if (!Collections.disjoint(command.getRequirements(), getRequirements())) {
         throw new IllegalArgumentException(
             "Multiple commands in a parallel group cannot require the same subsystems");
       }
diff --git a/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelRaceGroup.java b/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelRaceGroup.java
index 538ab11d5d2..bd2b214d106 100644
--- a/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelRaceGroup.java
+++ b/wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/ParallelRaceGroup.java
@@ -51,7 +51,7 @@ public final void addCommands(Command... commands) {
     CommandScheduler.getInstance().registerComposedCommands(commands);
 
     for (Command command : commands) {
-      if (!Collections.disjoint(command.getRequirements(), m_requirements)) {
+      if (!Collections.disjoint(command.getRequirements(), getRequirements())) {
         throw new IllegalArgumentException(
             "Multiple commands in a parallel composition cannot require the same subsystems");
       }
diff --git a/wpilibNewCommands/src/main/native/include/frc2/command/Command.h b/wpilibNewCommands/src/main/native/include/frc2/command/Command.h
index 4b508cfb194..c4af1afe81b 100644
--- a/wpilibNewCommands/src/main/native/include/frc2/command/Command.h
+++ b/wpilibNewCommands/src/main/native/include/frc2/command/Command.h
@@ -484,6 +484,7 @@ class Command : public wpi::Sendable, public wpi::SendableHelper<Command> {
  protected:
   Command();
 
+ private:
   /// Requirements set.
   wpi::SmallSet<Subsystem*, 4> m_requirements;