Zenith sieges would be in similar boat that bombards in AI hands. They are large low cap units that are balanced for player with strict cap which AI can ignore completely.
And for sieges it's the additional sticker on a hull: "I kill champions(and other heavy stuff)". It makes it more.. annoying than bombards probably.
Sigh...
Once again, it needs to be said, the AI does not
completley ignore ship caps. The AI will get less ship of a low ship cap per reinforce/wave/whatever than they would of gotten if they chose a normal ship cap ship, based on the ratios of ship caps.
It is important to note this is impacts how many ships the AI gets of a type; the game does not force the AI to keep their current counts consistent with the ship cap ratios.
For example, the AI is free to pick to reinforce with Seige Engines 20 times in a row. However, they would get only 1/4 as many as if they chose, say, fighters 20 times in a row. (or is the Seige engine's cap 1/8 of normal? If so, it would be 1/8 as many Seige engines)
So yes, the AI can somewhat ignore ship caps, but not
completley.