Visa invitation letter - immigration fraud

We have quite a number of people who want to register for our event free of charge. They even send us e-mails explicitly asking us for free registration.

Other people register without actually paying. We then have to remove these registrations from the database. Is there a proper way to deal with this problem?

(A German version of this article is available.)

There is not really a way to avoid this problem.
Many people simply register and hope that they will receive a visa invitation letter from you. This can especially happen when your event is renowned or widely publicized.
Registration cannot be limited to certain countries (e.g., by IP address), as there are many ways on the internet to disguise the location of your PC.

What you can do, is to enable "Pro Forma Invoices" in ConfTool.
To enable this option, go to:
Overview => Settings => Main Settings for Participant Registration
and enable "Issue Pro Forma Invoices First", available in the section "Invoices and Taxes" (see screenshot).
 
This allows you to confirm each registration or cancel it at your discretion.
The advantage is that a registration with pro forma invoices will not create an invoice number. So if you want to have consecutive invoice numbers (e.g., for accounting reasons), this usually helps.

Even if payment was mandatory for registration, it could make the problem of this particular immigration fraud scheme even more severe: It's easy and cheap to get hold of stolen credit card information on the internet. The fraudsters would use the information to pretend to pay. However, the owner of the credit card will notice that later and cancel the payment (Card holders always have at least 60 days to cancel any credit card payment).
These chargebacks will cost you (as the "merchant") a fee of about €25-€40 per transaction.

It may get even worse if the fraudster pays with his/her own credit card or transfers the money to your account. If the fraudster then actually arrives in your country with your invitation letter, but does not show up at the conference and just disappears after arrival without ever returning to his/her home-country, you will get into trouble with the immigration authorities.
This is not a theoretical problem, we know cases where these things happened and conference organizers were suspected of facilitating people smuggling.

Our advice is only to issue visa invitation letters to trustworthy participants!