However, if you find yourself at odds with a DM who tells you, "no, you can't do that" the outcomes are as follows:
- Humbly accept the ruling and continue in the game. You are very likely to have a good time anyway.
- Insist you be allowed to do it anyway, appealing to the group if necessary. You will soon have no campaign (either the campaign will fold or you will appeal, lose, and be asked to leave the group) and also run the risk of alienating most of the people at the table.
Based on the possible final outcomes that bubble out of the above choices, it seems to me that unless you are in a truly remarkable situation (as mentioned above, an example would be a group of very experienced players where everyone takes it in turn to DM for a month or so making the DM role a shared responsibility) the best course of action for the long term health of the campaign as a player is to humbly accept the ruling and move on, and the best course of action for the long term health of the campaign as a DM to take is to stand your ground and refuse the player's request - as every time I've seen something else tried over the past 40 years and over a dozen gaming groups (not just D&D but multiple TTRPGs), it has always led to the quick death of the campaign at hand and often resulted in bad feelings among the players - just a negative experience all around