In many types of cases, there may be physical evidence that the parties need to inspect. Assume a slip and fall in a public space at a mall. Can the plaintiff, his counsel and expert witness inspect it whenever they choose? The spot is accessible to the public, why not?
Baugus v. CSX Transp., Inc. considered this topic. The plaintiff sued CSX, a railroad company, under FELA. After he sustained the injury, but before suit was filed, he and two other individuals who were not parties to the lawsuit created a video. “They created the film, which purports to show one or more of the individuals performing activities similar to those required to load and unload the rail cars.” As suit had not been filed, no leave per Rule 34 had been granted. “No prior notice was given to or permission obtained from Honda Motor Company, which owned the siding on which the cars were located, or from CSX, which had placed the cars at that location. The filming occurred in the Springtime in the middle of the night. Plaintiff had been injured in the Winter at about 1:30 p.m.” 
Baugus first concluded “[t]here can be no doubt that the plaintiff created the tape in anticipation of filing suit. … [T]his tape was purposefully made surreptitiously and ex parte manner solely to create videographic evidence for later litigation.” With this fact determined, the court concluded the video would not be admitted at trial. “Among the purposes of Rule 34(a)(2) would appear to be to prevent exactly this sort of undertaking.” Rule 34 contains safeguards that both permit a party to access physical evidence, but to also protect the party who possesses the evidence. One safeguard is “an opportunity for the other side to be present and have the assistance of counsel. Such assistance helps ensure that what is seen or done is pertinent, and that any record that is created is accurate. Such assistance also lessens the likelihood of later dispute or challenge to the admissibility of evidence about what was done or seen.” A second safeguard of the Rule is that it enables “a court, rather than a single party, to decide whether to permit entry, and if permitted, to prescribe its conditions, also allows a balancing of the degree to which the proposed inspection will aid in the search for truth against the burdens and dangers created by the inspection.”
Where a party acts unilaterally, this balancing cannot occur. Where the party has gone at night into a rail yard to film others climbing on and about rail cars and manipulating equipment and appurtenances, it would have been especially appropriate to have obtained prior consent or judicial approval, if consent were withheld, for such entry.
Risk of injury is a constant feature of railroads. This is especially true at nighttime, or when unexpected trespassers are on the property. The risks are doubled, at least, when trespassers not only enter unannounced, but do so under cover of darkness. Indeed, one can assume, from the timing of the entry, that the plaintiff and his companions took precautions not to be observed – i.e., to conceal themselves from others who may have been doing their jobs, ignorant of their presence.
In short, if you want to inspect physical evidence that another controls, do not do it surreptitiously.