Much of "Why do casino check ID?" is settled on the sign up form. Registering at an online casino takes a few minutes, and the form asks for more than a username. Name, date of birth, address, phone number and email are all used later, to check age, to match payments and to recover the account. Details typed carelessly at sign up are the most common reason for a verification problem weeks afterwards, so the form deserves a careful first pass.
Registration usually asks the player to confirm legal gambling age and to accept the terms, the privacy policy and sometimes marketing preferences. The age confirmation is checked later against a document, and an account opened by someone under age is closed with deposits returned and winnings void. The casino also checks where the player is connecting from, since a licence covers some places and excludes others, so playing while travelling can be blocked for a while.
An email link and often a code sent by text message confirm the contact details before the account opens fully. Both matter later: the email receives withdrawal notices and password resets, and the phone number may serve as a second factor at login. An inbox that nobody checks or a number that has changed makes recovery slow. Marketing consent is a separate tick box, and leaving it clear does not affect the account at all.
The name and date of birth on the form have to match the identity document exactly, including middle names where the document shows them. The address has to match the one on a bill or bank letter. Payment methods are later checked against the same name, so a card or wallet in another person's name will be refused. Nicknames, shortened names and old addresses create mismatches that support can fix, although only after a delay.
Casinos allow one account per person, often per household, device or payment method, and a second account can get both closed and winnings withheld.
Usernames are often permanent, so choosing one carefully at registration saves a support request later.
The ticked age box is checked later against a document, and an underage account is closed with deposits returned and winnings void.
No; marketing consent is a separate tick box, and leaving it clear does not change anything about the account.
Exactly as on the identity document, including any middle names, because nicknames or shortened names create mismatches support fixes only after a delay.
The email receives withdrawal notices and password resets, and the phone may act as a second login factor, so outdated contacts slow recovery.