That's exactly what the email says. What's written in the email does not suggest that it's always the case. It mentions that it's "usually" the case. Plus I got the extension email one week before the deadline. I'm hoping it's delayed due to security screening but I can only be sure once I recieve the notes.
Usually or not, that entire statement in that email is false and misleading.
Beyond that's it's just coincidence that file is undergoing security screening and an ATIP extension was taken as well.
from CBSA
We do not take extension for any checks or updates on the applications. The role of the Access to Information Office is to provide existing documents under the control of the institution.
I have also included below, information regarding extensions as per the Access to Information Act, section 9.
Extension of time limits
9 (1) The head of a government institution may extend the time limit set out in section 7 or subsection 8(1) in respect of a request under this Part for a reasonable period of time, having regard to the circumstances, if
o (a) the request is for a large number of records or necessitates a search through a large number of records and meeting the original time limit would unreasonably interfere with the operations of the government institution,
o (b) consultations are necessary to comply with the request that cannot reasonably be completed within the original time limit, or
o (c) notice of the request is given pursuant to subsection 27(1)
by giving notice of the extension and, in the circumstances set out in paragraph (a) or (b), the length of the extension, to the person who made the request within thirty days after the request is received, which notice shall contain a statement that the person has a right to make a complaint to the Information Commissioner about the extension.
Marginal note: Notice of extension to Information Commissioner
(2) Where the head of a government institution extends a time limit under subsection (1) for more than thirty days, the head of the institution shall give notice of the extension to the Information Commissioner at the same time as notice is given under subsection (1).
Analyst, Strategic Policy Branch
Canada Border Services Agency / Government of Canada