Strange behavior in datatable

Hi, I have a datatable with a column of type datetime, there is a situation where someone assign a message in this column, something like "hello world", and it´s not throwing an exception. I know that should not be, I can´t find a why it happens.

I check the column of the table in the database and its type is smalldatetime, also check the store procedure that brings data, and makes no conversion, finally, it uses a datareader to get data

Any idea why not throw the exception?

Datatable lobjTable = lobjPrest.FindData();

if (lobjTable != null && lobjTable.Rows.Count > 0) {

lobjTable.Rows[0]["Date"] = "Hello world"; //This column had datetime format

}