[morzh]

It is acceptable but not desirable.
Plastic is not an approved cap dielectric, and even though a reasonably thick piece will have a good voltage breakdown rating, it's dielectric constant's behavior over temperature range is not guaranteed to be stable.
I do not know if it is good or bad, but I never researched this. We do know that this material is not used in caps, even though some plastics (polyesther etc) are used, but then again, they are not as stable as mica or some ceramic (NP0/C0G) types. This is why the performance might not be as good. Grtanted, today's radios are not everyday use/main communication device as it used to be, so it might not be as important, but still this has to be considered.

Or, as Jesus referred to this practice of breaking rules:

"On the same day, having seen one working on the Sabbath, he said to him, O man, if indeed thou knowest what thou doest, thou art blessed; but if thou knowest not, thou art cursed, and art a transgressor of the law."