Personally, I believe that, as poets, we need to be clarifying the regulations with the competition organisers ourselves.
When we write seeking clarification (and it should be in writing!) and receive an answer, we are then free to further contact the organisers and express our concern or reasons as to why a regulation may unfairly limit our eligibility, and/or affect our willingness to enter their competition in the future. We are also then free to offer suggestions on alternatives that we feel may enhance their comp entries.
My belief is that, as David says, most organisers have used a form taken from another competition, and are solely focussed on their own competition. They most likely have never considered the effect such regulations (ie not having been published) may have on the future viability of their competition, and would possibly be only too pleased to review their regulations in light of our comments.
If they are not interested, and are rigid in their beliefs without even considering constructive criticism, I would venture to say that they are probably competitions that you would not necessarily be worried about missing!!
Generally, if you encourage someone to look at an issue from another point of view, most reasonable people will at least consider your options, even if they ultimately chooose to continue with their original idea. If they don't, don't enter the comp!! There are many ways to raise these issues without upsetting the organisers - feedback is always a very important aspect of ensuring your competition continues.
Just my humble opinion!!

Catchya
IRene