Preapproved Payments (Adaptive Payments) & NonAccounts

Question

I've done several hours' worth of searching thus far, both through the API and various web resources + search engines (and SO), and the vibe I'm getting thus far is that you cannot setup Paypal preapprovals without a Paypal account. Accordingly, my adaptive payments setup always routes users to a Paypal checkout page where they can login to Paypal or create an account (no option for guest account, etc).

Okay, I get that. What I'd like to know, though, is how some sites still offer users the option to enter their credit card details (without requiring a Paypal account)? Crowdfunding is a popular use of preapproved payments right now, so the example I'd point out here are sites like indiegogo.com.

If you go through the motions of making a contribution to a project, you'll see you can either go directly to Paypal, or pay via credit card (which later takes you to Paypal). If preapprovals are limited to Paypal accounts only, how do they have the credit card functionality (without an account) built in? Are they just utilizing another area of the Paypal API?

Any links to documentation, suggestions, etc are welcomed :)

EDIT: So from @Andrew Angell's reply, did some digging and (from my limited understanding) it seems the best way to create the system I want is to setup a transaction via DoExpressCheckoutPayment for 0 dollars & setup a billing agreement. Once the buyer accepts the agreement, I can pull the agreed funds at a later date without need for further input from the buyer. This creates a system similar to the Preapproval transactions, but in contrast to Preapprovals this method allows for Guest checkouts.

Answer 1

I just took a look at their PayPal checkout and it redirects you to:

https://www.paypal.com/webscr?cmd=_ap-payment&paykey=AP-3F225210H0465832H

That is a regular Pay request, not a Preapproval. If they were setting up a preapproval that link would be:

https://www.paypal.com/webscr?cmd=_ap-preapproval&preapprovalkey=some_key_here

Answer 2

From PayPal's website:

To turn the feature off, simply go to the Profile subtab, click on Website Payment Preferences under the Selling Preferences column, and check the yes/no box under PayPal Account Optional.

*This feature is available to Premier and Business account holders only.

To turn it on, do the opposite. Note the last sentence.

Source: https://www.paypal.com/cgi-bin/webscr?cmd=p/mer/WAX_landing-outside

Note that your question isn't really a programming question and perhaps shouldn't be asked on SO.