If i connect to a website with LWP::UserAgent and fetch the whole website, does it count as if i've "entered" it in a browser ?

Depends. If the website contains swallows, then the browser may download the European variety, while LWP::UserAgent will get the African ones. To get round this, you need to specify this in the setup stage:

$ua->type('European');
$ua->using('Coconuts');
$ua->dorsal_fin->tie();
[download]

Of course this still won't help if your connection is lighter than a duck.