High Hedges and Pollarded Trees Offer Security

I was staying away recently with a family who have spent ages building the most fantastic extension on their already large family sized home.  I have watched the progress over the years and now that the guest suite is well on the way to completion, I find myself staying there more often.  There are one or two areas I would have given more thought to.  The windows in the suite look out over the garden, and it would be lovely to leave the windows open but I found these upvc ones had no locking mechanism where you could open it a small way and a screw on securing a device which locked the window in the open position but did not allow anyone access.   There are no top windows which would have been just as lockable in open.    The garden itself is private and reasonably secure.  There are no overlooking houses – in fact the property is surrounded by massive hedges, at least 3 metres high.  An additional benefit is the public cemetary immediately next door, the other side of yet another tall hedge of over 3.5 metres height.   There are English Plain tress which have been pollarded so there are no lower branches for any young varmit to climb up – even if they could fly the 2 metres from a branch up to the roof of the extension!  It all seems very promising when you look at security.  Less points of access, lots of visible internet cameras dotted along the various gutters and from the roof gables, does also deter the would be cat burglar.