smoooothstroke said:
How would they get the players to not open with a safe break?
Previous to 1910 they didn't use break balls, that is, instead of re-racking after 14 balls had been pocketed, they re-racked after 15 balls had been pocketed.
The beginning of each rack was effectively the same as beginning the game again however the points accumulated from rack to rack. All 15 balls were racked, cue ball behind the head string and you had to call a ball off the break. Which means they played safe at the beginning of each rack.
This was the championship game from 1888 to 1910.
The addition of the break ball gave a reliable ball to call on the break and continue their runs from rack to rack.
I would not be surprised if I were to learn that some professionals chose not to use a break ball, and still played safe. I have heard numerous times that Frank Taberski was known from running 15 and playing safe.
Some further research is required I think.
To answer the question more directly though, it does not force them them abandon safety breaks, but the benefits of avoiding an uncertain exchange would too much to ignore for great players. That and the prestige that eventually came with producing high runs.
*If there are flaws in my history, I apologize as I am reciting from memory, I'm going to look into this further*
P.S. If you can't tell I'm a history buff
EDIT: Changed a date to maintain credibility.