In the United States we have a test for the activities of the police. The tests are enumerated in the United States Constitution. U.S Citizens are protected from random search and seizure of property including your film and camera. There are a few laws (National Security & children) that may limit your rights to photograph but the police do not have the right to destroy your property (film) without a Court Order.
Having said that, if a cop hassles you, don’t resist. They have the nightstick and the gun! You have the courts to uphold your rights and seek redress.
First Amendment:
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
Fourth Amendment:
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
Fifth Amendment:
No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offence to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation.
George Minerich