Reps asked to sign a possibly secret contract without their consent

So to put into context, my company is in a bad spot. Revenues declining, cost cutting and turnover ever more relevant themes, you know the jist of a dying organization.

To keep the salesforce motivated in times of horrifying toxicity (those to hit target in the last four years can be counted on one hand), senior leadership recently came up with a would be nice if not very likely unattainable SPIFF. There was a SPIFF Launch event with a massive banner that was never plastered to any wall, just still remains lying on a table. During the event lo and behold, senior leadership made it awfully awkward asking reps to sign this banner, not a document, to celebrate this moment, a moment of reps commitment to a disgustingly unrealistic number they were forced to forecast in order for the organization to save its ass and look credible to the business. Many signed. What worries a lot of the reps that I know in that organization is the fact that they were explicitly asked to sign their own names with this number, clearly.

Could the company use this as a ruse to create a legally binding contract whereby failure to meet the number signed against could warrant rep dismissal?

Thanks