Preventing paste from overwriting cell formatting in Google Sheets

Question

I have a spreadsheet used for booking employees onto training sessions. It's very simple to use; the person booking simply enters their employee number into column A and column B, C & D auto-populate the employee's first name, surname and section using VLOOKUP formulas linked to another sheet.

Column A, where the employee enters their employee number, is the only unprotected column and is subject to data validation to prevent invalid employee numbers from being entered, but here's the problem:

If a user copies and pastes their employee number into column A, often the formatting is overwritten with the source formatting where the user copied from. To make matters worse, often the data validation is overwritten too! To resolve this, would any of the following be possible?

1. Somehow restricting the cells so that only Paste Special > values only is possible.

2. Somehow make the cell correct it's own formatting and data validation whenever data is pasted in.

3. Preventing copying and pasting entirely for column A.

Answer 1

Does the person making the booking really need access to the spreadsheet? Would it be better to make a Google Form which they enter their number and the course into, and which then puts the data into another sheet which has all the helper columns to fill in the rest of the details.