Can A use reasonable means to prevent B from subjecting A's daughter to familiarities?

The answer is indeed that A can use reasonable means to prevent B from subjecting A's daughter to familiarities if it is a potential threat. This is consistent with the legal principles surrounding the protection of minors from inappropriate interactions.

In tort law, a parent has a responsibility to protect their child from harm or inappropriate conduct by others. This duty of care extends to ensuring that the child is not subjected to situations that could lead to emotional harm, physical harm, or inappropriate familiarity. If B's behavior is perceived as threatening or if there is a reasonable belief that it could lead to harm, it is within A's rights to intervene and take reasonable actions to prevent that potential harm.

The concept of "reasonable means" implies that A's actions should be measured and not excessively forceful. The degree of intervention should be appropriate to the level of threat posed by B's actions. The focus is on the potential risk to A's daughter rather than an immediate or actual harm that must occur before any action can be taken. This principle helps safeguard children in various situations where their well-being may be at stake, encompassing more than just physical threats.