For each of the following ethical situations involving business transactions, indicate what accounting concept has been violated or whether there is no violation:
1. A sales transaction is recorded on the first day of the fiscal year when payment was received even though the service for the customer was completed in the year before.
2. A laser printer in excellent condition purchased at a garage sale has an estimated value of $150, but is recorded at the $50 paid for it.
3. A purchase of truck fuel is recorded as an expense (instead of as an asset) because it will be used in the current period.