When you have a motivated market driving by a higher demand than the supply, then yes you will find buyers making at or above listing price offers. Of course, this may not be an across the board action as prices will move upward to satisfy the demand. If you hear that a property is getting multiple second time showings, it may be a good idea to raise your offer price.
As to your wholesaling question. Wholesalers are looking to make a profit. Their current formula is (ARV x 60 - 70%) - Rehab Costs = Wholesale Price. Anything greater than 70% and they are going to have a hard time pulling a profit.
Know your comps. If you know the ARV of the home you will be fine. You need to make sure that your offer is never to high. Better to be to low. You have to make sure its a deal attractive to you and your buyers. :bobble