For the Quebec region, we could easily standardized a grenade model (IMO), keeping in mind we all go to the same area to get our pyro stuff. (same one to get cheap cigarette and fuel...).
2 black cats (for reliability)
1 small dentist like cup
a bit of masking tape to wrap it up
Those have been around for 5-10 games in Quebec, there are cheap and easy to make, no incident reported so far (to my knowledge). They don t create crazy shockwave and the like...
If someone use a crazy device (airbomb and the like), he get the same sanction as running around with a 400 fps AEG in CQB let say...