This feature is being rolled out for some upcoming walks that are likely to fill up.
We don't have a proper wait list for full walks (Eventbrite's waiting list doesn't meet our needs), but we can offer to notify you via email when a space opens up. Everyone that has switched on notifications will receive an email, so you may need to be quick!
The email we have for you is
If you'd like to use a different address for communications from our site, please contact us.
When a walk is full, switch on the 'notify me' toggle on the walk page:

Following this, you'll be emailed when someone cancels.
If you successfully register for a space, switch off the toggle to stop getting emails.