Application via mail - times

[alea]

Hello,

I am from Serbia and want to apply for temporary visa (tourist visit) in Canadian embassy in Vienna. I will send the documents via mail in few days.
My trip is due on June 7. I know it's a little late, but I will have to take the risk.

My question is related to this sentence from Canadian embassy's site:

If you are applying by mail, please note that completed applications should be sent to the Canadian Embassy at least 12 weeks before your anticipated date of departure.

Is this a rule or recommendation? Will my application be automatically discarded because I didn't follow the 12-weeks rule, or it will be still taken in consideration (with a risk of not getting the visa on time)?

Thank you