Data point: Work & live in Madrid.
Flew IB for a two week work trip, returning on a Friday night and baggage with office clothes missing.
By Sunday afternoon baggage was still missing and was given an OK by IB to buy clothes.
Claim submitted and just the reimbursement approval.

Don't know if it helped but at IB baggage counter when getting the PIR, I showed the agent pics & "evidence" of the work trip, which they added to the case notes.
Those notes could be seen by the phone agent later & possibly helped them give the OK to buy clothes, which facilitated getting the reimbursement approval.

Thank you to the fellow FTer for the guidance!