It is illegal
Yes, it is illegal to ship any artifact containing ivory, which includes pool cues, into or out of the U.S.A. Mainland or any U.S. territory for that matter.
For what it may be worth, this is what I've learned about the ivory regulation......I do my best to follow this closely because I have a vested interest in it.
In order to ship a pool cue or any artifact that has ivory, it must have a CITES certificate attesting to the fact that the ivory is pre-ban ivory dating prior to 1978. If someone were to claim that the information in their pool cue was pre-ban ivory, the chief biologist at the US Fish & Wildlife Service in Washington, DC told me on our phone call that they can check. The problem is it involves drilling holes through the entire cue taking core sample from the ivory claimed to be pre-ban ivory. It literally involves testing every inlay, ferrule, joint, ring, and butt cap. The verification process would literally destroy the cue because as he stated it, we really don't care about being careful.....just get the job done even if it meant snapping the cue in pieces.
There's zero liability to the US Government for any destruction of personal property as a result of verification of the ivory in any artifact. The bottom-line is don't ship anything into or out of the USA if it has any ivory unless you prepared to lose it. There's a cue right now in Cologne, Germany that I'm trying to buy but the seller hasn't any way of bringing it into the USA unless he transports it as personal property on a visit. It's a very fancy Ed Prewitt cue loaded with ivory and the cue would be confiscated and permanently lost if he tried to ship it. There's a chance it might not het inspected but we're talking a $5k pool cue.......who in their right mind is going to underwrite that risk......no seller ever would and neither will any buyer.
If the pool cue with ivory isn't already in the USA, just forget about it. But domestic sales of pool cues with ivory is totally permissible. But don't worry about penalties if you got caught and were the buyer. The regulation clearly states "it is illegal to sell ivory"......it bans the sale of ivory. The regulation does not say the purchase of ivory or the purchase & sale of ivory and is singularly specific.
As such under the law, it is not illegal to buy a pool cue with ivory; the seller may be screwed but not the buyer. In order for the buyer to be charged with violating the regulation, the regulation needs to be re-written. The ivory ban regulation is not subject to the US Constitution so no one could ever say this regulation violates their constitutional right to buy or sell a pool cue that contains ivory.
Can someone please clarify for me whether it is currently illegal to ship cues internationally from the U.S. with ivory in them?