I agree with the poster that said you can't take a student that doesn't want to go. (poaching)
My first experience (as a bystander) with a poaching accusation was a little different and eye-opening. It's the reason why I'm so committed to doing things ethically as a coach. (This story starts like a bar tale, lol. No booze was involved.)
Back in the day before cell phones and email, a coach was in a car accident and injured, unable to work for weeks and weeks. She taught at five different rinks each week and had students all over the place, literally. She arranged for a substitute at some of the rinks, but missed one that was too far away for anyone to cover her lessons. I'll guess that she didn't speak with each client personally. I think she left some of the notifications to the grapevine, especially those at the faraway rink. Her fault? You betcha! She lived alone and was on major painkillers, so I could see cutting her some slack.
The faraway skating rink/club needed a group instructor, so they brought in someone new to the area. The group students liked her. She started teaching privates to new students on Club freestyle and made a good impression on everyone. She also gave out free coaching tips, complimented the parents, suggested training drills and off-ice programs. (No one was a PSA member, but these are classic techniques of soliciting as the PSA defines them, as sk8dreams pointed out earlier.)
Several of the injured coach's parents asked if she could give lessons to their skaters. She said yes and never spoke to the injured coach. Parents never spoke to the injured coach. The injured coach never followed up with anyone to see what they were doing during her rehab. Major communications breakdown on everyone's part.
The scene upon the injured coach's unannounced return was so dramatic that the Club and rink owner had to mediate in a back room. I was just a bystander, but I personally thought they were all wrong. One family was asked to leave the rink/club because of their behavior during the meeting and a Head Pro was appointed to deal with all private lesson situations and coaching changes to keep it above board. (A paid position because no one would want to do that for free. It added onto the club costs, btw.)
Poaching doesn't mean accepting new students from other coaches. It means that the parents/students were solicited to switch coaches. Sending an email or flyer to other coaches' skaters about a program that you're coaching can be considered solicitation. It doesn't have to be the coach, either, it could be a well-meaning parent, a skating director/head pro, or a fellow coach telling someone "Your skater should take a few privates/try this group program with Coach A, she's excellent."
Save the drama - be an adult when wanting to switch coaches. One quick email or phone call won't hurt anyone.