There are some concerns related to the storage location being defaulted in shopping cart.
In PPOMA_BBP, storage locations are defined under "Extended attributes" tab, but no default flag is set.
Then, when end user creates a shopping cart, storage location is being defaulted, even if no default is set in PPOMA_BBP.
This is the expected behaviour. When storage locations are configured in PPOMA_BBP, even if no default is configured, system will consider the first storage location from the list and assign it to the shopping cart (respecting the combination of plant/company code).
This logic takes place in method STG_LOC_GET_DEFAULT of class /SAPSRM/CL_PDO_SHARED_USER (topic 2.3):
ELSE.
* 2.2 no default storage location => check if other stor.loc. exists
READ TABLE it_storage_location INTO ls_storage_location
WITH KEY plant = iv_location
logsys = iv_log_system.
IF sy-subrc = 0.
* 2.3 take first storage location as default
cv_default_storage_location = ls_storage_location-store_loc.
ELSE.
CLEAR cv_default_storage_location. " not available
ENDIF.
ENDIF. "sy-subrc 1.1
ENDIF. "cv_default_storage_location
For more information, read wiki page http://wiki.scn.sap.com/wiki/x/WIlKF.