Hotel systems and source-of-truth boundaries
PMS, CRS, channel manager, revenue system and CRM represent different operational truths. Availability, rate plan, reservation, stay, guest profile and housekeeping action should not be collapsed into one generic hotel tool.
Results must identify taxes, fees, cancellation policy, occupancy assumptions, validity and source. Guest preferences are personal data, not permanent permission to reuse them for every purpose.
Guest-facing and operational separation
Public guest capabilities and internal housekeeping or maintenance tools require separate roles and exposure policies. A guest client must never discover employee-only actions merely because they share one server process.
Modification and payment flows revalidate the reservation and current rate, protect against cross-booking access and record the exact state transition for recovery and audit.