Cheap easy ways to prevent guitar theft (and gear theft)
I've learned quite a bit on how to prevent gear theft over the years. There are many methods of gear theft prevention, but here are the ways I've found that actually work.
Know that anything that can be carried by one man will always be stolen first
The first step towards gear theft prevention is gaining knowledge. And the first thing to know is that whatever can be carried by one guy is what gets stolen first. Always.
This means that guitars, pedal effects, microphones and so on can be stolen easily. It also means that larger items such as a 4x12 cabinet cannot just for the fact it's so huge and would be very difficult for one man to haul around, even if it's on wheels.
Most thieves are dumb enough to believe a sign
Let's say you're forced into the situation where you have to leave your gear somewhere unattended, such as in a practice space.
Assuming for the moment your friends (as in your band mates) aren't thieves, placing a sticky note on the neck of your guitar with "Broken electronics! Do not use!" is usually enough to stop a thief from stealing a guitar. He's not exactly going to plug it in and check because that would make noise and he'd get caught.
Sticky notes work for basically anything. "Broken, do not use" can be put on mics, amplifiers, pedals or anything else.
In fact, you could put all your carry-able stuff in a box, then just put a sticky note of "Everything in this box broken, do not use". Make sure that sticky note is really visible so a thief would see it. If a thief ever breaks into the practice space, he'll see the sign and most likely ignore anything labeled "broken".
Use a busted 4x12 guitar cabinet as a storage area
Thieves will not steal 4x12 closed-back cabinets because they're just too large to move, and you can use this to your advantage.
Buy a cheap used guitar cabinet, and if possible, get one with blown speakers.
Take the bottom two speakers out, put adhesive Velcro on the four corners where the speaker screws go, and cover the speaker holes with two square sheets of black fabric.
Whenever practice ends, take off the front grill, remove the black fabric over the speaker holes that's held on by Velcro, put all your microphones and pedal effects inside, put back the black fabric sheets and then reattach the speaker grill.
While this isn't a foolproof way of hiding your stuff in a practice area, it's certainly better than nothing.
If the practice space allows it, build a steel cage out of old steel grates
I knew a few bands back in the day that used to do this, and it always worked well.
Back where I used to live in New England, guys used to rent practice spots in old mills. These were old-ass buildings where you could basically build whatever you wanted in there since the owner didn't care.
Guys in bands around the area were mostly blue collar types, and as such had access to things used on construction job sites either for cheap or free. One of these things were thick steel grates. These guys would cut these grates in such a way where they'd build a large cage out of them and use a corner of a back wall in the practice spot to put the cage together. On the front of the cage was a fabricated door on thick steel hinges.
If you're thinking, "That sounds almost like they were building a prison cell", that's not too far from the truth because it was basically constructed that way.
When the band was done playing, all the stuff went in the cage (drums, amps and all) and was usually locked down by a large steel bar with a large padlock at the end of it. And the padlock was mounted in such a way where it was next to impossible to get a set of bolt cutters in there to cut it loose.
To add even further security, the band would put black sheets or tarps over the gear once in storage so any would-be thief couldn't see what's in there.
I can say for a fact that guys in bands who stored stuff like this never had their stuff stolen. Even the most desperate of thieves wouldn't put all the effort forth of busting into a thick steel cage without knowing what's in there first.
Take it home with you
This is the best advice on this list. When you're done with a gig or done with practice at the practice spot, take all your gear home with you.
Yeah, it's annoying to lug around all your stuff whenever gigging or practicing, but that is the #1 way to keep your stuff from being stolen.
Oh, and one final note. If you haven't done so, write down the serial numbers of your guitars or at least take a photo of them. It doesn't matter if your guitar is worth $10,000 or $100. Do it anyway. If your axe ever gets stolen, that's the only thing that can really identify it.