Plan which files you genuinely need on the trip and how you will recover them if the phone is unavailable; an encrypted vault does not determine border-search powers.
Separate travel convenience from exposure
A phone used for tickets, navigation and family photos can also contain work records and identity scans. Decide what must be available offline during the trip, what can remain on a trusted device elsewhere, and who can help if the travelling device is lost. This decision is easier before departure than while someone is asking to inspect a phone.
Make the plan recoverable
Prepare a tested backup and keep the recovery material somewhere other than the phone that may become unavailable. Check whether the documents you need are stored in ordinary downloads, messaging attachments or cloud accounts as well as a vault. Removing one local copy does not change all of those destinations.
Do not interpret a decoy interface or destructive control as assurance that a search will stop. Applicable powers and obligations depend on the journey and jurisdiction. Get current advice from an appropriate qualified source before travel when the consequences matter; this page does not establish your legal obligations.
Where NullVault helps
Offline local use can keep a chosen private archive accessible without a NullVault account. Separate pattern-addressed vaults compartmentalize ordinary access. Those features do not promise protection from coercion, an observed pattern or a compromised endpoint.
Use the private-photo threat model and encrypted-backup checklist. For people travelling on reporting assignments, the Committee to Protect Journalists' digital safety kit is a starting point for a broader assessment of devices, accounts and communications.