When the ball is kicked out on the full it doesn't result in a scrum.
Ive seen Alibert ref 2 Quins games this year and to be honest have enjoyed the games. He lets the game flow. Having said that at times he can be a bit weak and his hand signals need to improve.
Having done a bit of reffing the most difficult decisions for me were when the ball comes lose when there are players on the floor. You are unsighted. To give a penalty, which is what sky were suggesting last night, when you haven't seen an offence cannot be right, no matter what you may be thinking. Additionally the ball carrier has a duty to protect the ball.