There's really not much need for installing locking strap buttons or finding other alternatives than using these rubber strap blocks that are based around the little rubber seal (or what it's called) that is used on resealable old timey glass beer bottles. Although, if you have a thicker guitar strap made of leather, you might find it hard to put the strap blocks on, it can get quite tight. Also, if you've got larger strap buttons, these strap blocks could be more diffcult to put on. But so far, out of nine guitars I've tried, including a bass and an acoustic, there hasn't been a guitar that they didn't work perfectly on.
Just make sure your strap buttons are nice and tight, you don't want those guys loose not even a little. Check them regularely!