Short answer: No. Employees who waive because they have other valid coverage are removed from the participation math, which makes it easier to hit the carrier’s threshold.
Carriers set a minimum participation level (often around 70 to 75%), but they calculate it after subtracting employees who decline because they have other valid coverage, a spouse’s plan, another employer’s plan, Medicare, Medicaid, or military coverage. Those “valid waivers” come out of the denominator, so a group with several validly-covered employees can still qualify even if raw enrollment looks low. Waivers without other coverage do count against participation.