I have employees that are service techs. They're out in the field all day. They go thru drive-thru for breakfast and lunch. stop at the store a couple times a day. Then they write on time card "no lunch" so then they have 9 hours from 8-5 so they have overtime. Do I have to pay them for this?
You need to clarify your working day. You need to adjust your contract to say that the employees 'are required take an off the clock lunch of 1 hour'. I have seen this before, and it would protect you from employees milking you for 'overtime'.
Your contract should also state that overtime must be approved in advance by management.
Tread carefully though, you can't require your people to work lunch or drive between worksites on their 'lunch hour' if you require them to take one.
They may also walk off a job site at 5:00 if they are not allowed to work overtime without prior authorization.