Wishpicks asks "Who's opening this list?" when it can't tell if you're a gifter or the list's owner, so the owner doesn't see what friends have reserved by accident.
Got the link from a friend? Tap I'm a guest. Is it your own list? Tap It's my list. Until you answer, the list behind the window shows nothing about reservations, and the window has no close button. A link to a single wish asks first too, then opens the wish.
When does a list ask?
Only in a browser the list can't place: not signed in as the owner or a helper, holding no reservation on it, and with no earlier answer for it.
The owner isn't asked where they're signed in, or in the browser they made the list in without an account. Nor are people with Full Access or Contributor access.
Reserved something on the list in that browser or account? It doesn't ask you.
Signed in to your own account? A list that belongs to someone's account asks you only if it has a greeting card.
A list with reserving turned off asks only if it has a greeting card.
Collections never ask, and a list you can't open shows "No Access" instead.
Your answer is kept for that list in that browser. Another browser or device, a new private window, or clearing this site's cookies asks again.
What happens when I tap I'm a guest?
You see the list the way every gifter does: which wishes are taken, but not by whom, with Reserve and Only what's left. Reserving counts as an answer too, so the question doesn't come back in that browser. The rest is in "How do I reserve a gift?".
What does It's my list offer?
It opens "Keep the surprise?", which explains that this browser would show you what friends have reserved. Back returns to the question, and the other buttons depend on the list and the browser:
On a list in an account, while this browser isn't signed in: Sign in to edit. Once you're signed in, you're back on your list as its owner, and reservations stay hidden unless you've chosen to show them.
When this browser is signed in to another account: Switch account. It signs that account out first, then opens sign-in.
Always: Browse without spoilers, to look at your list here without any reservation marks.
Always: Show what's reserved, to see the list as your gifters do, taken wishes included.
A list made without an account has no sign-in here. To edit it, see "Can I recover a list made without an account?".
What does Browse without spoilers show?
Your list with every reservation mark left out: no Reserved chips, no Reserve buttons, no reservation filters, and only the wish count at the top. You can't edit or reserve from there, because this browser isn't signed in as you. A strip under the header says "Your list, no spoilers." with Not my list, which brings the question back.
How do I change my answer?
After Browse without spoilers, tap Not my list in the strip. If you've only tapped It's my list so far, Back takes you to the question.
I'm a guest and Show what's reserved have no undo button. On your own list, there are two ways back:
If your list is in an account, sign in on that browser. It then shows you the owner's view, whatever you answered.
Or clear this site's cookies in the browser's settings. The next time you open the list, it asks again.
Show what's reserved in this window changes only what this browser shows: your list's own setting stays as it is, and gifters see nothing new. It isn't the Show button beside "reservations hidden" from "Can I see what's reserved on my list?".
Tips
Checking what friends see? Use a private window and tap I'm a guest: closing the window forgets the answer, and your usual browser keeps the surprise.
On someone else's phone, pick Browse without spoilers rather than Switch account, so their account stays signed in.
Want the window to greet your guests with a note? See "How do I add a greeting card to my list?".