Well I guess aside from the fact that surface mounted contacts tell the whole world exactly how your alarm works from a glance across the room, the only difference would be that surface mounted contacts can be disabled by virtually any tradesman possessing minimal knowledge, less than 60 seconds of time, and the tools/supplies they normally carry. Also after they disable the contact only a close inspection would reveal the tampering.
For example:
painter: break off razor blade after cutting into wire
cable guy: wrap fine filaments of cable wire shielding between contacts/temrinal screws
phone guy: wrap single strand of stripped cat3 between contacts/terminal screws
plumber: piece of solder wrapped between contacts/terminal screws
carpenter: nail/screw into wire
I'm still trying to think of the trade that normally carries a suitable magnet.
In short, disabling surface mounted contacts is a simple crime of opportunity whereas disabling recessed magnets requires pre-meditated intent as well as an opportunity to closely inspect the window.
Gatchel, look into Nascom's switches. In between their BMS' and recessed contacts, it'll supplement most requirements for security and not be the large "safe" contacts of old. Magnaspheres still aren't commonly stocked items for most trade distributors, but they're out there. We've been using them for about 4-5 years now. It still won't address a person getting to the wiring and compromising that, but getting units with integral EOLR's is the option. If you have people that have the time and abilities to access wiring to compromise it, you've got larger issues to address.
@ Lou, reread my post, I put the suggestions out there before others provided the handy links. If someone's going through the efforts you've listed, it's not a crime of opportunity and nothing is going to stop them.They can pull a recessed contact and do the exact same things you're listing as caveats for surface contacts just as easy and just as fast in doing such.For that matter, I might as well just fire up a welder on your property and create some EMP to take care of the system...just as quick and easy. In the scenarios that you listed, a properly installed EOLR (or even though I'm not a fan, EOLR's inside the contact) would detect the defeat methods you started detailling (to a point), but the argument is still going to be academic.
If the concern is wiring, and access to such, then wiring routing methods should be implemented to avoid the scenarios you noted...there's no reason a cable would be exposed if the install is performed properly, nor would screw terminals or other compromise points exist.
A standard recessed or surface mounted reed switch can easily be compromised with a strong enough defeat magnet. Hell, most trades and even standard people carry a rare earth magnet of some sort. My newest torpedo level has ones that'll overpower most magnets that come with the contacts. Magnetic pickup tools are another one. It's not even like it needs to be a "standard" magnet...just look for the closest speaker.
Not going on a tangent, but speaking from experience and dealing with high risk sites, assets and places subject to repeated compromise attempts, many times I've installed multiple switches and detection circuits, hell, even dummy contacts for the specific purpose of creating the "tamper" event. As I said, if security is paramount, a single, normally closed detection circuit with a single closed contact being installed is not going to be how it's done.