Escorted off the premises was SOP for anyone at my last company, even if all you did was give two weeks notice. If you told them you were going to work for anyone remotely considered a competitor, bam – here's a box to collect your things while someone watches over you, then out the door you went. Anyone laid off got the same treatment.
The trick to not being frog marched out the door was to tell them you were going to take some time off.. Of course then you had to come in every day for two more weeks and listen to your boss whine about getting those loose ends tied up* and doing knowledge transfers.Pick your poison
When I left I chose to keep my dignity, but I still took all my personal stuff home well in advance of giving notice – just in case. I took time off – Saturday and Sunday – before starting at my new company.
* I might have been more diligent about tying up those loose ends if I hadn't lost a bunch of vacation time due to them changing the vacation accrual policy the year before. Basically they stole my accrued vacation time right as I was about to take a month's vacation. I still had a negative balance when I handed in my resignation and they dunned my final paycheck as a result, fucking bastards.)