I work in the insurance industry.
Travel insurance is not designed to cover camera equipment. Its main objective is to cover emergency medical expenses. Where baggage insurance is taken out (usually an optional extra) cover is usually very modest and usually applies ONLY when another more specific insurance does not exist i.e. if you have your camera covered under a home insurance policy or under an All Risks policy then usually the travel insurance baggage section doesn't cover you. Why? Simply because of the risk of you accidentally on purpose dropping or losing your gear is too high. Who can blame them?
Make sure that your individual item limits are high enough for each of your individual items of gear and that your overall limit is high enough to cover all of the gear in your camera bag.
All policies have some sort of excess to avoid the high administration costs of small claims and to keep the cost of the insurance lower.
Usually the excess only applies to each loss so if you had a camera body stolen with a lens, filters, flash unit and tripod attached, only one excess would be applied once.
Make sure that the single article limit under the policy is not lower than the total value of all the items described above. Some policies would cover up to the limit and you would be out of pocket for the difference. Others would not cover it at all. Ask the insurer how it would be handled in the event of a claim. Remember when doing the calculation you need to work out the value of the equipment with your most expensive body, lens, flash unit, filter, tripod etc.
Despite having insurance (if you have arranged it properly) remember that you are still expected to act as though you were not insured and look after the equipment. There is a duty of care. You need to act sensibly and look after the equipment.
Finally remember that if you do not act sensibly or are just plain unlucky and you have several claims, eventually the insurer will decline to insure you. Then you will find it very difficult to get cover at any price.
So my advice is check that the insurance covers you for the value of all your equipment that you would ever have in the same place (i.e. could be lost or damaged at the same time), check that the individual limits are high enough for your equipment (and ask the insurer to increase the limit if they are not) and finally look after your equipment as though you didn't have the insurance.
