I agree with sree on one point - hold a meeting by department, not the full compliment of employees, only those who have been habitual lates/ tardys.
Remind them of their responsibilities to the Company, and Co-workers.
The Company pays for a full day’s efforts. If an employee is late (s)he cannot provide the service that has been legally and morally contracted for. In fact, they are stealing, at best and committing fraud at worse.
Co-workers rely on their presence to help solve problems, integrate concepts, and assist in the efficient flow of work. Absence due to lateness holds up the work of colleagues. That’s like having a spring break in a watch. A simple component leads to devesting results.
I’m not a big proponent of rewarding employees for accepting and recognizing their responsibilities. Reward should be meted out for extra-ordinary achievement. To provide rewards for on-time attendance, lessens the impact and diminishes the substance.
Nor do I think that “sweets or cakes” is the answer. Suppose an employee refuses? What will happen? Will you let them leave work to get the “sweets or cakes” ? (Employees will be clamoring to be the last one in.)
Similarly a “best late comer award” and/or “late comer cap” (to be worn all day) is, in my mind, insulting, demeaning and will have little or no impact on the offenders. In fact these kinds of things are apt to cause dissention, lower morale, and create the basis for more challenges to management’s authority.
Likewise for the “Treasure Hunt” - I believe that it will further delay of the start of work. Employees may refuse to be lured into the hunt, or, in the alternative, go around, possibly outside their work area, looking for the “Treasure”. Meanwhile, nothing productive is being done and other personnel are being distracted.
You have a serious problem that can spread and affect the morale of the rest of the workforce.
What would happen if a non-“pampered” group (Admin, for example) began to come in late? If discipline would be imposed, it would be discriminatory, since management has already approved such behavior in another group within the Company. If they did nothing, the message to the rest of the organization is that coming to work late is the norm for the Company.
Before long the whole organization is in chaos. Everyone coming to work at a different time; setting their own hours; leaving before the end of the shift. If that is what Management wants - Flex Time - then they should announce a new policy. If not, they must be prepared to enforce the one they have.