Non-unionize employees are safer?

I would like to know what screening methods unions use other than police checks. 

His comment about losing control of who enters the property was kind of funny.  strangers ride the subway every day.  there are no security scans.  anyone could bring whatever in.  a simple piece of paper on the tracks could cause chaos. 

The ttc even advertises the paper cup issue in the ttc cars.

I am sure if there are special procedures for scanning then it could be listed in their contract and if not done ttc could sue them and get out of the contract. 

I look forward to comments.