Smarty condition | $var should behave like '{var}'

If I use a Smarty-condition in standard form (as described at http://www.smarty.net/docs/en/language.function.if.tpl) while I don't use the variable elsewhere, the condition doesn't work.

Example (broken because $contact.gender isn't used):
Liebe

{if $contact.gender eq 'Mann'}

r

{elseif $contact.gender neq 'Frau'}

/r

{/if} {contact.first_name}

Example (workaround):
Liebe{if '{contact.gender}' eq 'Mann'}r {elseif '{contact.gender}' neq 'Frau'}/r{/if}

{contact.first_name}