For perspective, the thing EFBs primarily replace is paper charts and approach plates, which are probably a worse FOD hazard due to how many different ones you have to use on a long flight. Most military pilots are trained to “dummy-cord” or otherwise secure anything that can become a FOD hazard inside the cockpit. There are plenty of products out there that let you strap a tablet to your leg at least as securely as a traditional kneeboard or IFR strap.