You are probably better off using a linked record field for which event they want to work. Limit the linked record field to one record in the filtered view. That way, if there are changes to the number or name of events, the form will still work.
Hello,
In Order to do that you need to have a single select field with the name of the event in your table.
It is a two step process to set it up
Step 1 : Initiate
Add a text field "Events"
Fillter your table on status "confirmed
copy/paste content of field "Title" into field "Events":

Change "Events" field type to "Single select" (I suggest to uncheck "color-code options" because this option does not make sense if your have too many events):

Step 2: Field Events maintenance
In order to avoid maintaining this field manually, you can create an automation triggered when status is confirmed:


Action update record to push the Title field value into field Events and hence create the new option:

Now, if we consider following table with Event 1 not confirmed yet:

If we change the status to confirmed, Option "Event 1" is created into Fields "Events" and this record takes the value "Event 1":

Field Events can now be used in your form as you wish
Regards,
Pascal
You are probably better off using a linked record field for which event they want to work. Limit the linked record field to one record in the filtered view. That way, if there are changes to the number or name of events, the form will still work.
@kuovonne , @apowers
My apologies, I started writting my answer before Kuovonne posted hers.
Kuovonne's solution is the right one, mine will not work for the purpose of having a sign up form.
Regards,
Pascal
Hello,
In Order to do that you need to have a single select field with the name of the event in your table.
It is a two step process to set it up
Step 1 : Initiate
Add a text field "Events"
Fillter your table on status "confirmed
copy/paste content of field "Title" into field "Events":

Change "Events" field type to "Single select" (I suggest to uncheck "color-code options" because this option does not make sense if your have too many events):

Step 2: Field Events maintenance
In order to avoid maintaining this field manually, you can create an automation triggered when status is confirmed:


Action update record to push the Title field value into field Events and hence create the new option:

Now, if we consider following table with Event 1 not confirmed yet:

If we change the status to confirmed, Option "Event 1" is created into Fields "Events" and this record takes the value "Event 1":

Field Events can now be used in your form as you wish
Regards,
Pascal
Thank you @Pascal_Gallais-, that worked!
However, then when I fill out the form, a new record is created. Whereas I wanted the staff person to be tied to the same record as the event title. Is that possible?
Filling out an Airtable form always creates a new record. I suggest having a two table system, one table for [Events] and another table for [Event Staff]. Use a linked record to join the two tables together. Build your form in the [Event Staff] table and use the linked record field for picking the event.
Note that your staff will only be able to create new records with the form. If you want them to be able to edit their existing records, you can either use an interface or a third party portal. Both systems will have associated costs, although many people find third party portals to be more affordable.