In "old" Stealing, yes it helped.

In new, there are two things (primarily) which help us, Perception, and Trading Skill.

Trading mainly just helps us to KNOW when we've been stolen from, perception helps us to see/stop the actual attempt.

Stealing Skill, if close to (or above) perception, will actually "help" the contest, but surely not as much as perception skill itself.

...Though, remember, if you are stolen from you can ignore the person and move on. If you steal (or even attempt to steal) from them, they CAN and sometimes WILL attack you for it.

just like you CAN attack them if you deem your combats as a trader as up-to-snuff.