Not trying to draw out attitude but rather help you with your inquiry. Here is how...

The lighter is held to the cable that cinches the bag shut. The cable is thin braided wire so melting point of thin steel is lower than the temperature that a lighter flame gives off. That looped cable at the top is all that holds the bag shut. When that's gone the bag is open. To most people, it looks like it was cut.

The lighter is less conspicuous for your maid to walk into work in and out of work with. She's not going to carry around bolt cutters every day just in case she sees an opportunity. A good number of the maids are probably smokers anyways so she can't be definitively pinpointed. I'm not telling you how so you can go do it... just that you can't rely on these to provide any measure of protection when they're left alone. Your threat is not a smash and grab, pickpocket, or someone running away with the bag (what it is designed to protect against). It's someone who has a period of time alone to gain access and sort through your belongings.

I see you're in Baltimore. The lighter method was very common with bike theft in Federal Hill during the last couple years. Carrying around a lighter is not illegal but wandering in back alleys with bolt cutters could be incriminating. Anything with a cable lock behind houses was pilfered. Bikes and grills secured with chains and heavy locks had a better chance being left alone.

The bag (1) draws attention to the likely presence of concealable valuables (stuff smaller than a laptop) and (2) is easily exploited with something your maid probably already carries. It's your stuff, your $70, and your call but just my $0.02