No, Most of them are not.
Check out the following and decide for yourself
Most of the agencies won't ask you for a registration fees. If they ask for it, do check the credentials of the agency and ensure that you are going in for the right agency by confirming the previous work profile. If they are a well known name in the modelling industry and you are being asked a nominal amount as an annual charge or a registration fee, it's at your discretion if you would like to pay this amount and sign up with the concerned modelling agency. However, this is not a confirmation that you will get the modelling assignments for sure in return.
You have been selected for an Assignment ! This is another trap. You will be told that you have been selected for a modelling assignment and now you require a Portfolio which needs to be done through them. Well, if you have already been selected based on your passport or random image, why should anyone even require a professional modelling portfolio. so, they are only interested in making money through the portfolio which they will make. You have no idea if the portfolio, you are going for is good enough or not.
You have been selected for an assignment in a different city - To ensure that you will turn up for the shoot, you need to pay a security amount. This tactic is very popular with the parents of the kids, who wish or I would say are quite desperate to see their kids as models.
You have been selected for an assignment in a different country - You may get an email that you have been selected /shortlisted for an assignment form a different country. We all want to go abroad and it all sounds so great that you have been selected by a prestigious International magazine. After your photographs, the "Agency" or the Scout / representative will most likely ask you for the scanned copy of your passport. Any other identity won't do. Then he/she will ask for your bank details so that an advance may be transferred to you. What could go wrong? You are too glad that you have got an assignment. With all the required information the concerned person is actually trying to withdraw the money out of your account. be very careful before you give away your passport and Bank details together.
I have shot several portfolios of models and taught photography to several aspiring photographers. The reason why I am aware of such incidents which some of the new comers come across and keep warning them against such things. Always check the credibility and reputation of the organisation before going ahead with any project. Also, ensure that the terms and conditions are favourable to all. If it all sounds and seems too good to believe do check with caution.
At the same time, you don't need to be extra careful when you are dealing with reputed names in the modelling industry. Most of them won't do any thing to affect or harm their own Image and Reputation. I always suggest and guide my models to the most reputed modelling agencies and Casting Directors so that they are always in safe hands. Rest ofcourse it depends on their own talent and efforts as well besides having a good portfolio.
Photographers or Modelling agencies can't give you a commitment of work or assignments. A lot of people, whom I have not even seen, ask if the work is guaranteed when they inquire about a modelling portfolio on phone. If I have not even seen a person, how can I even comment on his or her chances of getting any work.
Confidence and an understanding of reality are very important. Aim for what you are made for. If you are heading for something, which is not your cup of tea, look for an alternative and enter the world of modelling accordingly. Once you prove yourself there may be other options open for you.
Unpleasant encounters usually happen when you are or show your desperation to the other person. If you are confident about yourself and you are good at your job, you don't need to be desperate and if you deserve you certainly will get a chance sooner or later. Follow the right path. Promote yourself. Make contacts. Circulate your images. Go for Auditions. No one can get you somewhere faster, not at a cost at least. favours may work. But not if you are not good enough. maybe to pickup the best amongst equals. or to give you a chance to be in the race. But you have to win the race on your own. You can get into a contest but winning is absolutely your own game.