@Oliver Keates, there are plenty of outlier situations, of course. Also, most moves that can get you in trouble happen outside of the GMB dashboard, whereas most missteps in GMB will only prompt Google to auto-update / overwrite your info (rather than pull your page).
Anyway, here are what I'd say are the most common apparent causes of suspension:
1. Completing owner-verification at an address that has (a) no online listings (i.e. citations) other than GMB and that (b) shares the address with at least one business in the same industry or category. To Google, often that tends to look like you're trying to splatter with the map with pins.
2. Creating too many GMB pages for a business that tends to operate as an SAB (whether or not the addresses are hidden), especially if the addresses used to verify those pages are close together, like in the same city. Google wonders why a pest control company, for instance, has 4 "offices" in the same city.
3. Making too many changes at once, including changing the same field back and forth too many times. You'll want to spread out edits.
Keep in mind that a lot of the trouble one runs into is at the hands of attentive (or disgruntled) competitors who send in Google Maps edits that stick. Google itself doesn't pay that much attention and dole out most suspensions spontaneously. More often, Google removes a listing that someone has called its attention to. Most of it is crowdsourced.