As far as guys holding out after being tagged, history is in the Rams favor. As far as being
forced to trade AD, a look at this has worked out in the past would indicate that the Rams best option would not to trade him, demands or not.
Paul Gruber held out for 7 weeks after being tagged. He even worked out a contract with the Raiders but Tampa and the Raiders couldn't agree on a trade and Gruber signed and reported.
Lomas Brown held out after being tagged by the Lions, he missed one week before signing.
Sean Gilbert held out an entire year before signing with the Panthers and the Redsking recieved two first round picks as compensation.
Dan Williams held out an entire year but eventually signed with the Chiefs, his home team.
Simeon Rice held out for one game before signing with Cardinals.
Walter Jones held out two games before signing with the Hags.
For the guys mentioned that demanded trades and were traded, again we see little similarity to the AD situation.
Jay Culter trade request was a result of a fued with McDaniels and not related to money. He also wasn't holding out. When he was traded, his contract went with him.
Bryants beef with the Steeler was not about money but about how much he was getting the ball. He also wasn't holding out.
Dickerson held out missing 2 games in 1985, but reported to the team and later signed a contract. Dickerson was traded, how'd that work out for the Rams?, but it wasn't because he was holding out and it wasn't because he demanded a trade. When he was traded by the Colts, he had completely alienated the team and coaching staff and had actually been suspended. The Colts were ready to move on from him. When they did trade him, his contract went with him. Nothing like the AD situation.
Palmer was not holding out and was under contract and when he was traded the Raiders assumed the contract. Also the Bengals were ready to move on from Palmer and the dispute was not about money, rather his future with the team.
Speaking of the Bengals, Chad Johnson held out and demanded a trade in 2008. The Bengals refused to trade him, and actually refused an offer from the Redskins that included a first round and additional picks. Johnson returned to the team to complete the season. Although he was traded after the season - a trade that did not include a contract negotiation.
So the only guy that held out and demanded a trade at the same time did not get traded. As for the rest of them, their disputes were not about money and in each case the team was not all that interested in keeping them in the first place. Again, not like the AD situation.