"[A table in this article] summarizes certain facts related to the wellness programs at issue. The employee incentives involved in these cases are significant; employees who elect to forgo participation in the programs lose 'incentives' such as eligibility for health insurance coverage or 100% employer-paid premiums.... Although it is clear from the complaints that the EEOC believes the penalties at issue render the wellness programs involuntary, the complaints do not shed much light on the threshold at which an incentive is deemed a penalty that renders a wellness program involuntary."