Let's say you're in a supermarket on the day before Christmas and there's a huge 20-person line to each register. Assuming you knew exactly how much the goods in your cart are worth, would it be a crime to leave said amount of money to a random employee (e.g. the information desk) and then just proceed to leave? By "crime" I refer to a situation where you can be charged with theft.
As Dale M explained, if you give the money to someone who is not obviously authorized by the business to accept money and sell stuff in exchange, you have not entered into a valid sales contract.
That means you are taking things without permission. Therefore the shop could sue you for any damage this causes (maybe you took something the shop did not want to sell, or the person at the information desk was not an employee and ran away with the money).
However, whether this constitutes a crime such as theft will depend on jurisdictions.
In Germany, for example, it would probably not, because by definition a theft requires "intention to take posession in violation of the law" (StGB §242). You could argue that you did not intend to violate the law, because you paid the required amount, and only gave the money to the wrong person by mistake. Of course, I cannot guarantee that will convince the judge...
England and Wales
Similarly, the law in England and Wales defines "theft" in section 1 of the Theft Act 1968:
A person is guilty of theft, if he dishonestly appropriates property belonging to another with the intention of permanently depriving the other of it; [...]
Furthermore, section 2 says:
A person’s appropriation of property belonging to another is not to be regarded as dishonest—
(b) if he appropriates the property in the belief that he would have the other’s consent if the other knew of the appropriation and the circumstances of it; or [...]
So, similar to the situation in Germany, you could argue in court that you intended to buy the item legally, and believed that the shop would be okay with that.
You can only form a contract with an organisation by making an agreement with an individual who has the capacity to bind the organisation.
A person operating a check out ostensibly has the ability to contract: a person packing shelves or mopping the floor does not. If that person does not have the ability to contract then the customer has not entered a contract with the supermarket even if they give that person money!
Taking the goods in those circumstances is, technically, stealing.
NO. By handing out the money to a random employee, you do not avoid criminal charges under theft provisions.
This is because the purpose of theft protection is not to make sure that the owner remains in the same economical position. Its purpose is to make sure that the owner of property keeps in possession of his property, thus can enjoy it or dispose of it as he pleases. Therefore it will not suffice that you handout a substitute that has the same value as the property. This becomes apparent where a person owns a beautiful and valuable painting. He wants to enjoy the painting and not the money it can be exchanged for. It becomes even more apparent, where the property has no economic value at all. For example, a drawing by a beloved child and its only value is the affection it expresses to the father.
That said, by handing out the money to the random employee, ownership of goods is not transferred to you. This requires a sales contract, and under German law an additional contract for transfer of ownership due the principle of abstraction between contract and transfer of ownership.
A contract requires both offer and acceptance. One could argue that your handing out of the money is subjectively an offer, but objectively it is not. A reasonable person would not interpret the offer of money an offer to a sales contract. The presentation of the goods is the offer, the money the (maybe necessary) consideration for transfer of ownership.
By taking the monies the random employee is not aware of an offer and thus cannot accept it. This is supported by the fact that he probably does not see the specific goods. Consequently, ownership is not transferred. The goods remain property belonging to another, which may result in a charge of theft.