You can limit the numbers of attendees by removing the option to bring extras.
Deleting the option for people to bring extras will not affect guests who already clicked the +1 choice, only guests who are signing up after the change will be affected.
Remove option to bring extras
To remove the option for attendees to bring extras, follow these steps:
Go to your event
Click on `Settings`
Click on `Setup`
Scroll down to the checkbox `Guests can bring extras` and uncheck it
β
β