Although a large % of QNers will be taken directly by banks, some will deal with HHs, and that is why our Guide has a section on dealing with us pimps.
Frankly as newbies you are more easily lied to, since your ability to spot being fed a line is compromised by this being a new game to you.
Yes, some HH firms names come up more often than others, and the story about a certain firm sending so many CVs it caused technical issues is true.
Some firms send your CV to firms without your permission, and I have personally seen a CV from a current employee arrive as if he were looking for a new job.
This can be very expensive.
Bonuses are driven by your future value to the business unit. If your manager thinks you will quit after getting this bonus, his rational action is to drop it to zero, and use it on more "loyal" staff. This is not a theoretical postulate of agency economics, but a real thing that happens.
Also your CV may get "improved", or as we say at P&D "fucked with".
Happened to me. Whem I last had a proper job, we needed an absurdly specialist skill, and a CV from an eminently qualified candidate appeared. I noticed something odd, that this person had been at one same employer as me. I would have remembered him, and about a minute later I realised that I was looking at a version of my own CV, so screwed that I did not immediately recognise it.
My CV had "acquired" experience I did not have at employers I had not worked at. They had also made the dates inconsistent.
One member of my team at a tier one bank was discovered to have done time in prison for theft. He had left that time in his life empty and hoped people would not notice. The HH had kindly filled it in with a bogus job.
But the killer is that when such stories come out, no one is surprised. There are >5,000 agents in financial markets, some bad eggs are inevitable, but we call ourselves pimps partly because we think violent drug abusing criminals who sell sex wholesale enjoy a better reputation than the sector we work in.
I hear far worse cases than make to Wilmott.com, and have seen a few directly.
A particularly bad trick is to claim that you will be in a different bonus pool or area than you really will be in. That is easier to pull because a "quant" may be working for a different group than the one you get paid from. One of our guys called this having a "daycare boss".
That can alter your cashflow by a factor 2, and dramatically affect your career path.
P&D don't name names (yet), but this is our nuclear option. The button is wired up, and I have the pro bono coordinator of one of the top 5 firms on the planet who has expressed the desire to defend with extreme prejudice free speech bulletin boards.