I actually use glue for a lot of things. When I cut things like Quadcopter frames or 3D skeleton puzzles I hate having to leave tabs to hold pieces in place. They can be a real pain to leave and I always seem to mess up my Z and either accidentally cut through the tabs or leave them so tall they’re a pain to get pieces loose.
I’ve also had issues with finding flat ply at my local stores…it’s almost all warped to some extent and won’t lay flat. I’ve also had problems with my work lifting up off the table if I only screw or clamp it down.
So what I’ve been doing lately is I cover the bottom of my workpiece with 2" wide strips of blue painters tape (or masking tape, but I find painters tape to be a little nicer to work with and not that much more expensive.) and then putting a matching layer down on my spoil board. Then I just glue the two layers of tape together. For smaller items CA glue on one side and a spritz of kicker on the other works great - glues instantly and doesn’t come loose. For larger pieces I’ve been using 3M industrial strength spray on contact adhesive. Two coats on each side - let it get tacky for a minute or two…then stick it down.
I could probably get by with a single coat of spray glue…but wanted to be safe. It works great everything stays in place - even little parts with no tabs! But it all comes up easily when I’m done even though it’s also strong enough to hold even the crazy warped ply I find locally flat.
And with my work finally held that well and flat I’ve finally got my Z consistent enough that I can actually cut through just the top layer of tape if I choose to now.
Oh, one other little benefit…my cuts come out a little cleaner since the tape helps keep this cheap ply from splintering as much.
The only downsides are it’s single use so does cost a bit…but a roll of tape and can of spray glue have lasted me through about 3 4x8 sheets of material. And if you do cut through the tape then it can leave tape residue on your bit and the edge of your cut.
(and yes, carpet tape works too…but…it’s more expensive, is harder to remove, and if you cut through it makes a much bigger mess on your cut and bit than the painters tape does. )