Smith and Warner will be donning the Baggie Green for the first time in England since they were banned for an year by Cricket Australia following their involvement in the ball tampering scandal which took place in South Africa last year.
However, Ali wants fans to refrain from heckling the duo in the prestigious quadrennial tournament.
"I really hope they don't get too much stick. I want them to enjoy the series. If you have to, keep it funny, not personal," Ali told The Guardian.
"We all make mistakes. We are human beings and we have feelings. I know deep down they are probably really good people. I just hope they get treated decently. I just want the cricket to be spoken about," he added.
Earlier, Australia head coach Justin Langer had said both Smith and Warner would require sensitive monitoring and handling over the coming months.
Both men played key parts in the recently concluded edition of the Indian Premier League (IPL) for their respective franchises, though they had to leave the tournament early due to the Australia camp.
While Warner bagged the Orange Cap after being the leading scorer as he amassed 692 runs in 12 innings for Sunrisers Hyderabad at an average of 69.20 and a strike rate of 143.86, Smith made a slow start for Rajasthan Royals but ended up scoring 319 runs overall in 10 innings at an average of 39.87 and a strike rate of 116.00.
Australia will begin their World Cup campaign against Afghanistan on June 1.