I probability should not mention this but just to be clear interestedparty you are worried about some check for 10K?
Those people handling your check get your annual payroll data. They know your SSN, how much you make a year, they most likely know your address. I could go on.
I know the pay of every employee from CEO on down for every company I help run their retirement plans. (I work on exclusively on ESOPs now but got my start in 401(k) work.) I know their SSN also. If I am going to commit a crime with this information it isn't going to be from some guy who thinks $10k is serious money.
All this information is needed to help your company run the 401(k) plan. Done wrong and someone is going to pay large fines to the IRS.
I would add if the loan is set up wrong that non-taxable event turns into a fully taxable distribution. If you are under 59.5 you would get to pay the 10% penalty for taking a distribution before you are 59.5. If the payment back to the 401(k) loan is not done right it becomes a taxable distribution. More can go wrong then you think. The end results can have a bigger impact then you think.
Lastly, like others I find it funny about the 10k. So you really think the people who work on your company's 401(k) plan make less then 10k/year? That is less then $5/hour.