Is jailbreaking the iPhone safe?

I don't mean like being hacked or anything as ive had a jail broken iPod touch for over a year now but seeing as the iPhone is in contact with O2 and things is it possible they could block my iPhone from the network for failbreaking. I'm also not worried about it voiding my warranty because as we all know you can use the handy restore as long as apple don't keep track of it :D

So I basically wanna know if jail breaking an iPhone is as safe as jail breaking an iPod Touch