We filed very quickly after deciding to do so. Therefore, we didn't wait 90 not using our cards as is recommended. See my post - why we filed when we did.
Two of our creditors contacted our lawyer with threats to object.
The first was a balance transfer we did around 60 or 70 days before filing. We transferred around $2500 from Discover to American Express for a lower interest rate. Discover contacted our lawyer and threatened to object. We decided to do nothing for the time being and see what their next move would be. Our lawyer did not think they would actually object because of the relatively small amount of the debt. We never heard from them again and they did not object.
Next we got a letter from our Wells Fargo credit card. This card was set up to be our overdraft protection on our credit card. We ran into that overdraft protection every single month before we filed. That card threatened to object based on the 60/90 day rule (balance transfers and purchases for luxury goods and services in the 60 days for cash advances and 90 day period for purchases are presumed fraudulent.) Our lawyer sent them back a letter telling them that we had record of all purchases and they were for auto fuel and groceries. They never objected and we never heard from them again.
I talk a little bit about the letter from Discover in this post after our 341 - http://www.bkforum.com/showthread.php?t=11265