Poached a Client

Today I called into a local business (a larger one) on a none seo/website related manner as they owed me some money from my computer repair business. I asked them for some advice and asked if they think businesses would be interested in my maintenance scheme. Basically he said yes we would actually do that it sounds good. and then he explained how his current website guy (some guy in my town who has actually done a fair few not sure on his age but I think its actually a decent sized business with lots of reputable clients and his wife works for him) hasnt maintained his website and was meant to call in etc but hasnt.

He asked if I could update it all and whatnot and I said sure explained what I would do and then explained my directories etc and they seemed fairly interested.

He then asked me what he needs off his current website guy so I explained as simply as I could I need access to the domain and what it does and why as they asked.

Although im pleased ive 90% landed my self a monthly client (not huge cash like $60 a month) im a little bit worried the old website guy who is local will know what im doing as he will for sure when they ask for domain details because my business is redoing it.

Do you think this guys going to be pissed? im also slightly worried he will copy my directory idea before I fully get it off the ground so any advice on safeguarding is welcomed.

Im not to paranoid as theres more positives .

Any of you guys had bad experiences poaching?

Firstly, congrats on getting some new business

The other guy may be pissed (who wouldn't be when loosing a client ?) but anyway he's the one who screwed up (he didn't maintain his client's website)
You didn't actually "steal" a client from him: the client decided to hire someone else (you) to do a job that haven't been done - and the client is king. That business and competition 101 .

Well apparently this new guy I got has a mate with another business the same in a different town. Ive actually done some work for him before (the other guy) but never mentioned websites to him as his business card had one on it. When chatting today though apparently this other website guy made a one for him last week... im gutted I wish id got in there first.