The program will check your profile against the required criteria for the assignment. If your score shows as a 5 your request will be rejected. It will tell you right then and there that's its been rejected. All the MSC utilizing Sassie start you out with a 5.
I handled this one of two ways when I began shopping. 1) Contact the scheduler directly (if they list their email) and plead your case. You can explain that you've been shopping for some time, but are new to their company. Some schedulers will work with you. Some can't due to restrictions. 2) Like you've eluded to, you work the crappiest job that MSC offers just to boost your score up.
I messed up my first shop with Intelli-shop. My initial score of 5 was lowered to a 3. When you get down to a 3 there are very few shops offered to you. After all, at 3, you're a loser. I managed to find a phone shop that paid $2.00 one day, and I could do with a score of 3. I rocked that report and got a 10. I went right to a 7 after that shop.
Long story short, you've got to play the game. But, it can be done.
Shopping up and down the Colorado Rocky Mountain front range.