The only time a $100k+ bond would be reasonable is if they trained you from scratch, and paid for it all. Anything else is attaching a leash to you for no reason other than they can't be bothered to offer competitive salaries and want to trap pilots into servitude. Stay far away, there are so many better options out there. Remember that fixing yourself in one job for years might mean you miss the better seats while the music is playing, don't play their game while its in your favor...
If you are an instructor tell your students to avoid these people and so on. The end result is that they offer proper remuneration. Look at the mining industry, they cry so much that they need cheap international labor, when they cant get it they pay big bucks and offer FiFO and still make millions...