The problem with this technique is that now you have to inspect the seal every time you leave your laptop unattended.
Are there any other, more convenient techniques to defend against evil maid attacks?
Automatically clear some memory when the laptop is opened so the BIOS can tell.
Put important parts inside an epoxy. Add some transformer wire in the epoxy that will break when somebody tries to tamper with it.
I'm not trying to be exhaustive. But stuff like that.
Password keystroke surveillance (from sniffer, optical cameras or RF WiFi Sensing) can be mitigated by removable 2FA/smartcard.
TEMPEST info leakage from displays, components or RF implants can be measured, as SDRs and machine learning lower decoding costs, https://news.ycombinator.com/item?id=41116682
Some enterprise PCs can detect when the case cover is opened, e.g. http://h10032.www1.hp.com/ctg/Manual/c07055601.pdf
A locking briefcase (a cylinder key lock with 7 pins? - not sure of the correct terminology here)) may not stop an expert locksmith, but otherwise you can tell if the contents have been accessed. I have a fabric one (heavy duty fabric, cannot be torn by hand) with a zipper that is locked by key. I keep my notebook computer in it when I travel, either in the trunk of my car or my hotel room.
Or, when I took a multi-day train trip a few years ago, every time I had to leave my "roomette" (open access) and travel a few train cars away for a meal or sightseeing, I made sure the laptop was in the locked briefcase.
Edit: Also, even though we have been discussing only computers so far, the random mosaic method can protect anything. The top level comment shows how a similar approach can be used in pharmacology.