They do indeed keep the bowls open, as well as Blue Sky and most everything else as long as it is skiable. You may see an early lift closure or two but it will have a really minimal effect on you if any at all.
The trip off the mtn at the end of the day is the worst, but you can download on some lifts if you choose. You may and probably will find winter snow on the upper portions of the mtn. and if it has frozen up over night pick and easterly facing trail in the morning and follow the sun around the place and you'll be fine.
I'll be in the area (Summit County / Vail-Beaver Creek) from 4/1 -4/22. I think we are skiing BC on the 10th, their last day, but that may change. I'll be posting a schedule here around the 1st of the month.
I'll send you a "Vail Day Guide" I wrote for another member here. If you have never been to Vail, you will find it helpfull to find your way around the first day.