Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
No, ACL wouldn't impact traffic just moving between the two switches as L2. It will only impact the SVI which is used when traffic enters or leaves the VLAN via L3.
The ACL should be applied on both switches SVIs, both because both SVI interfaces might be used concurrently for entering the VLAN and even if one is the "hot" gateway for leaving the VLAN, it could fail then traffic would shift to the other SVI.
As to why it allows for traffic in either direction - from its (currently) described usage - that's unnecessary. Perhaps when it was defined it was also intended to be used as both an IN and OUT ACL.
