Deliberate deception, one example among some common ploys in international negotiations, refers to

Negotiators waiting to the last minute before the international negotiation team plans to go home.

One negotiator acting agreeable and friendty white his or her partner makes outrageous or unreasonable demands.

Negotiators making an agreement then reveal that it must be approved by senior managers or the government.

Negotistors presenting fagrant untruths either in the facts they present or in their intentions for the negotiation.