Is this realtor unethical?

[Shefali R.]

Hi - we just submitted an offer for a best and final process at 2pm EST today. The listing agent now says that they will come back with feedback on Friday (3 days from now). I have never encountered this before and sense that the realtor is continuing to fish for more offers. 

Is this unethical on part of the listing agent? Any action I can take to prevent this from happening again? Should i withdraw my offer to prevent it from being used as a fishing mechanism by the realtor? 

Thanks

Shefali