No One Can touch your Phone without your permission
In this case, the primary question is going to be whether the conduct at issue is harmful/offensive. Unless the museum guard had preexisting knowledge of the questioner's sensitivities, the "reasonable person" standard is going to apply--that is, would the contact in question be offensive to a reasonable person? If the guard did something like grab the questioner's arm or shoulder, this may perhaps be unprofessional under the circumstances, but it's unlikely to rise to the standard of being objectively harmful or offensive conduct. It's also likely that being a guest of a museum subjects one to policies regarding bags/purses/backpacks/etc., so there is probably not a complaint to be made about a backpack being touched. However, if the guard was lewd or overly physical, that would be another matter.
