Welcome, and thank you for posting here in the Roku Community, @hetoo!
Thank you for letting us know about this. No worries! We're here to help you fix this so they can't control your Roku device.
This is just a friendly reminder that IR-operated Roku remotes do not require pairing with a Roku device; they automatically pair. If they are using a Roku TV, they are most probably using the remote that came with it, which is also an IR-operated Roku remote.
Your standard IR remote uses invisible infrared (IR) light to send the signal a short distance from the remote (where the IR transmitter is located) to the front of your Roku device (where the IR receiver is located).
A Roku Voice (enhanced) remote needs to be paired with a Roku device by pressing the pairing button. You can check the existing paired remotes on your Roku device under Settings > Remotes & devices > Remotes and remove the unwanted remotes currently paired.
In the meantime, you may visit our support article to help you learn more about how a standard IR remote works.
I hope you find this information helpful.
Best regards,
Carly
Carly Y.
Roku Community Moderator