Listen to the pool guys. Would you let your teenagers walk on your just refinished but not thoroughly dried hardwood floors? :-)

I would ask in the Expert Plasterer's thread to be sure....but according to the FAQs on the NPC site: "At no time should any person or pets be allowed in the pool during the fill. Do not allow any external sources of water to enter the pool to help prevent streaking. It is recommended that you do not swim in the pool until the water is properly balanced, sanitized and the there is no more loose plaster dust from brushing; however, entering the pool once it is filled with water will not harm the finish."

If there is any plaster dust, within a few days it can brushed and then vacuumed out to waste.

I see no issue using the pool provided the aftercare following the fill up is diligent. The first two weeks need much attention particularly the water chemistry. Usually within a few days the person managing the chemicals will have it balanced. The plaster will fully cure in 28 days. No salt for 30, wait 2 weeks before using auto cleaners. Brushing twice a day for 2 weeks. More if you are able.

If a spa is part of the package, do not blast the heat passed 85 for the 28 days. I have seen up close damage on a finish from excessive heat.

The care does not stop after that 2 week period. Weekly testing, adjusting and brushing is recommended.

How much money did you spend on the pool? Do think the pool guys are messing with you, or do they want the best possible outcome for the project?