_noms_ - That seems to be a one-off experience. Myself and many others frequently bring models and radio controllers into Doha, and it is really rare that we are questioned on it. And even if it gets seized, the most you will have to do is to talk to the Aviation center at the Qatar Scientific Club, which is the authority on RC in Qatar. You may explain the situation and get a letter from them, or they may ask you to become a member of the Club (which is really easy) or both.
In short, the hassles seem really remote (just not impossible though).
_noms_ - That seems to be a one-off experience. Myself and many others frequently bring models and radio controllers into Doha, and it is really rare that we are questioned on it. And even if it gets seized, the most you will have to do is to talk to the Aviation center at the Qatar Scientific Club, which is the authority on RC in Qatar. You may explain the situation and get a letter from them, or they may ask you to become a member of the Club (which is really easy) or both.
In short, the hassles seem really remote (just not impossible though).