I'm playing OotP on PS2 and I've just finished the part where Harry's in his last Occlumency lesson with Snape. One of the memories Harry's trying to block is of him and Sirius talking in the Family Tree room at Grimmauld Place. It got me thinking about the severe lack of privacy.

Legilimens lets people break into your mind, face to face of course but still against most peoples will.
Veritaserum makes you spill your darkest secrets if questioned about them.
Prior Incantato makes your wand show what spells were last cast.
Fred and George's Extendable Ears lets people listen in to private conversations.

There are ways to counter Legilimens and the Ears but if you don't expect the Ears to be about you won't think to counter against them. And if you don't know Occlumency you're powerless against someone's mind attack. Casting a spell against them is effective, as we saw with harry and Snape, but it might be too late by then, they might have already gotten the information they wanted or needed.

The lack or privacy can be a good thing. Like if you've captured a Death Eater and you want to find out his masters plans, Legilimens and Veritaserum can be useful. But who governs it? We can assume that the Good side will only use these things if it is absolutely necessary but whose going to put the rules up for everyone else?

The Extendable Ears might seem like a laugh but, as we saw in OotP, they were trying to use it to get information not meant for them. Now what if the Dark side turned it round on the Order? We saw what happened with the Peruvian Instant Darkness Powder from Weasleys Wizarding Wheezes. It got into the wrong hands.

Prior Incantato can be useless if the caster is smart enough to cast others spells that wouldn't incriminate them, providing of course that the spell only releases a certain amount of previously cast spells and that it can only be used once on any wand at a time.

Now who knows how many other ways of invading privacy there are. Would any of you feel comfortable knowing that anyone could be listening to your conversation, or planning to drug you with Veritaserum so they can find things out?

I wouldn't. I'd have to guard my tongue and never say what I truly feel again, unless there was some assurance that it was only going to be heard and not passed on, by those I trust most. But even then, there's no guarantee they'll keep it to themselves.

What does anyone else think?

Well I definitely agree that these are all things that make privacy difficult in the wizarding world, but its not so different in the real world. There are tape recorders, people get bugged, tapped phone lines, lie detectors, and a whole myriad of things of that sort. Not to mention societies obsession with facebook and twitter that cause people to tell everyone what they are doing all the time, or people may post incriminating photos of you as well.

Yes I know that the things listed above are not full proof, and can all be tricked, but the same can be said of the wizard devices. You already stated how you could easily stop extendable ears. Legilimancy can be blocked through focus and occlumency or by breaking eye contact. Even veritaserum is relatively ineffective if the person knows they are taking it. Just like a lie detector can be tricked or wrong veritaserum can do the same. We see in book 4 that barty crouch jr confesses to his deeds under the influence of veritaserum, but is still brushed aside as a lunatic, so it is fairly safe to assume that veritaserum is not 100% effective or trusted. Prior incantatum is also similar to a fingerprint except that it is much more likely that a fingerprint would be left behind than someones wand.

I think the problem with privacy is just how society is in todays world. Yes the wizarding world has its own unique ways of invading privacy, but they are not necessarily worse or more effective than the way we muggles do it.

P.S. As for the comment about toys being weapons. Im sure you have seen those toy spy equipment things kids buy. These are extremely similar to extendable ears, and they could definitely be used in a way other than fun as well.