I mean i am not a lawyer.
In germany we have § 303 b StGB. In short it says if you hinder someone elses dataprocessing through physical means or malicous data you can go to jail for up to 3 years . If it is a major process for someone you can get up to 5 and in major cases up to 10 years.
So if you have a zipbomb on your system and a crawler reads and unpacks it you did two crimes. 1. You hindered that crawlers dataprocessing 2. Some isp nodes look into it and can crash too. If the isp is pissed of enough you can go to jail for 5 years. This applies even if you didnt crash them due to them having protection against it, because trying it is also against the law.
Having a zipbomb is part of a gray area. Because trying to disrupt dataprocessing is illegal, having a zipbomb can be considered trying, however i am not aware of any judgement in this regard
Edit: btw if you password protect your zipbomb, everything is fine
Telecom for example does Deep PackageInspection. That is rather well kown. Derec made a statement years ago that it is normal for other european isps too. Here is a secondary source for it, i cant find the primary source anymore https://netzpolitik.org/2012/berec-studie-dpi-bei-vielen-providern-bereits-im-einsatz/
If you are succesful in disrupting some dataprocessing doesnt matter, trying to do it is illigal. If you put it there to disrupt crawlers you are trying to disrupt an entities dataprocessing.
If your isp does dpi an archive bomb is able to crash their server. Even if they have measures againt it, it is still illigal because trying it is illigal.