Curious. I have never heard of transporting a table saw on its top.
I helped a pattern maker move his shop four times, maybe five, can't remember exactly. He has three Delta UniSaw table saws. We never tipped any of them their tops. I transported a used UniSaw to and from my home and did it upright. I helped transport a good friend's metal machine shop twice. All of these transports involved all manner of machines, including very heavy ones up to around 9000 lbs, many that were tall and/or top heavy (like Bridgeport mills and one 36" capacity bandsaw).
The key to safe transport of all items, particularly heavier machines and top heavy items are the tie-downs. I find the key to effective tie-downs is using a "V" pattern, where the apex of the "V" is at the tool and the two tips of the "V" are the tie-downs. When necessary, for heavy or awkward items, I use 4 of these "V"s, one in each of four directions, front/back/side/side.
Obviously, there have to be tie-down points around the perimeter of your hauling vehicle, trailer or box truck. The machine tie-downs, the apex of the "V"s need to be around some part of the frame or sturdy, non-moveable part. Use ratchet straps for pulling tension to secure the items. Manual pull straps are not capable of pulling enough tension. I do use manual pull straps on lighter items to set one side of opposing "V"s and then use a ratchet strap on the other side to pull the tension. But, I do not trust the grip/closer on manual pull straps for serious tie-downs.
An important aspect is to tie-down high enough, above the vertical center of gravity as much as possible and in ways that cannot slip or shift during transport. On something like a floor model drill press, the heads on many can be lowered, down the column. If that is possible, loosen the locking bold/clamp and lower it about half way, so the base/underside of the head is about even with the top of your trailer sides. Lock it again, making sure it is tight and tie-down over the top of it, if the cover will handle the stress. If not, tie-down around the column just under the head.
Sometimes, it is not possible to tie high. In such a case, tie the "V"s low to secure the weight of the load and also tie over the top in a way to keep it from tipping and down.
If you ever move a bandsaw - take the table OFF - and never wrestle a bandsaw by the table. Wrestling it by the table can/will twist it out of alignment and if the saw should topple, the trunions will get broken and replacements on older saws can be difficult to find. That doesn't even account for damage to the table should it topple. I happened once in the transporting I've done. Also, if something starts to fall, get clear of is FAST. You cannot stop the fall usually and trying to just puts your limbs and body in dangers way. The guy handling that bandsaw almost lost a finger as it got stuck on part of the table as it toppled.
On something like a table saw, in addition to using "V" ties around the base, I'd also put a strap over the top to keep it down on the deck.
Once you are secured and start to roll, stop a short ways (less than a mile) and recheck all the tie-downs. I check them all again after driving longer distances, every time I stop, which is often for "potty breaks" and a bad lower back that must be given straightening and stretching often.
"Quality is like buying oats. If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."