I just found a cool new feature on OWA – and best this is available on both Exchange Online and Exchange 2016 On Premises.
When you use OWA to setup a meeting request, you have the option to configure a message reminder (not the ‘classic’ pop up reminding you your meeting in 15 minutes)
The option to configure the mail reminder is available just below the ‘classic’ reminder option
When you configure this option, you have the choice to send the reminder to you or everybody as well as when you will receive it
Once you have configured it you can add, edit or delete the reminder at any time; even after sending the invitation.
And this is the message you are getting