The following quote is from Vaibhav Sagar, “From High Touch to Low Touch,” Global Trading, January 16, 2018 (https://www.fixglobal.com/home/from-high-touch-to-low-touch/):

Back in the day, most market making and client order execution was carried out by human traders. So-called high touch trading was often an opaque process, vulnerable to latency and susceptible to frontrunning.

Since there was no way for buy-side clients to monitor how the broker desks dealt with their orders, there was always an element of mistrust and misjudgment.

a. Explain what is meant by: “Back in the day, most market making and client order execution was carried out by human traders.”

b. Explain what is meant by: “So-called high touch trading was often an opaque process, vulnerable to latency and susceptible to frontrunning.”