[squid-users] when does squid check acl?

[Ilya]

Let`s assume, i have "acl day_time" and "http_access...", so 
that users are allowed to use proxy only between 8-00 : 17-00. 
Somebody   
begins to download some big file at 16-50, and it will take 
about an our. 
Question: will squid terminate downloading in 17-00? or let 
user to download his file.

When does squid check acl? When user requests 
http://host.com/big_file.mpeg ? 

wbr,
Ilya