The first time I let my rescue greyhound off the lead I thought I was in an enclosed space that he couldn't escape....
I was wrong :gasp:
He went through a barbed wire fence, through a hedge, over a stream, through another hedge, through another barbed wire fence THEN through an electric fence...straight into a feild of sheep..... Before I even had a chance to react :gasp::gasp::gasp:
I nearly peed myself.
FORTUNATELY he only had a sniff of the hedgerow and wasn't interested in the sheep, but he point blank refused to come back to me.
I tried calling nicely, shaking the treat box to screaming hysterically all to no avail.
He eventually came back (after I had scrambled through the fence/bush/stream/bush/fence/fence) but only once my lurcher started barking at him.
A year on and he can be let off the lead in a FULLY enclosed feild (by this I mean that it is surrounded by high strong metal fencing with no gaps. there are two gates, I stand guard by one and my OH by the other). He's fine with other dogs (But I don't trust him with anything smaller than our lurcher as he was attacked by a jack russell last summer and I don't know how he will react to one if he encounters another small dog)
On the lead I don't muzzle him, I am 100% confident I can control him and he is good as gold on the lead too. Also, even when the jack russell attacked him (the jackie had it's whole head in frisbies mouth as it attacked frisbies lolling tongue) the jack walked away totally unscathed (Poor friz had bites in his tongue and on his throat though

)
Frisby is silly soft with my own cats (of which there are currently 5) and i could bring a strange cat into the house and he would be fine. However, he half heartedly chases them out of the garden and I definately wouldn't trust him with ANY cat off my property.
Kids wise I trust him implicitly with ANY child, he would never hurt one on purpose unless he was asleep and a small child started bothering him- My kids are too big for that but IF i had anymore I would gate the kitchen off for him to have a child free retreat to sleep in. Another issue is his size, he seems to think he's a lapdog LOL. But I wouldn't leave him unattended anyway and out and about, on or off the lead I trust him. As I said, we guard the gates to the feild so if any other dogs or kids come in we just politely ask them to wait while we grab Friz. His recall is 100% perfect these days but only because we control his environment. I am sure that if he was presented with an opportunity such as on the first time he was let off lead, he would do the same again. (Squeeky bum moment for sure.)
Honestly, I don't believe he is a danger to any other cat or dog, but realistically I try to take as few risks as possible.
Lurcher goes off the lead though, she's very small (for a lurcher- i think we were lied to with regards to her parentage when we got her as a pup, we were told she was a greyhound x blue merle but i think it's closer to mum- greyhound x collie dad- collie) she's about the size of a springer. She's very submissive to other dogs (stop drop and roll) and not fast enough to catch a cat, not that she tries. She always comes back when called and really hates being on the lead.
Sorry for the long post.