If you want to ensure that no guide is placed on a trip without first saying yes, the Always Request Booking setting is what you need. When this mode is active, every assignment you make will require the guide to explicitly accept before it's confirmed.
How to enable it
Click your outfitter name in the top left and select Settings.
Navigate to the Org Settings tab.
Under Guide assignment mode, select Always Request Booking.
Click Update to save.
What happens next
Once enabled, any time you assign a guide to a trip they'll automatically receive an email and SMS notification with the assignment details. The assignment isn't confirmed until the guide responds and accepts in the app.
If the guide declines or doesn't respond within the Response Window you've set, the request will auto-expire and you'll be notified to assign another guide.
Assignment requests can occasionally land in a guide's spam folder. If a guide isn't receiving SMS notifications, ask them to check their spam and mark the number as not spam so future messages come through reliably.
For a full breakdown of all guide assignment modes and notification settings, see Choose How Guides Get Assigned to Trips.