This question is very similar to this one. It's about a hypothetical scenario in which:
- Party A (an individual or a company) writes a contract and sends it to party B
- Party B makes small changes to the contract, and signs it
- Party A signs the contract, but is unaware of the changes
The only answer to the question linked above states something along the lines of "it's a grey zone, theoretically it's legal, but don't try it" which of course is the reasonable answer to this type of scenario. But the following questions remain unanswered:
- Does B have a legal obligation to inform A that changes were made to the document?
- Is there any legal basis for A to argue that the procedure was dishonest, because they were expecting to sign "X" but they ended up signing "Y"?
Intuitively I would imagine that "I didn't read the document" is not a justification for A to contest the terms of the contract.
However, imagine the case of, say, loan contracts: considering 1) the length and complexity of the documents 2) the number of hours it would take for bank employees to read the thousands of contracts signed every year and 3) the significant financial incentive to be dishonest by changing e.g. the interest rate in the document, I would be surprised that nobody tried to kind of trick.
This question is not specific to the example of bank contract, or to a country in particular - though I'm mostly interested in Europe/North America. I'm just curious to understand what legally prevents this type of things from happening in general.