Automotive paint strainers work/flow well compared to coffee filters. Any fluid will pass through filtration before the pump sees it in this situation. As long as its a clean container to reclaim, and you filter it should be little to no risk. Biggest risk is using a dirty container. You are only trying to remove any possible hair, bugs, or trash from disassembly. Any metal glittering in the fluid was too small to be filtered by the pump filter, so no factor.
People introduce more trash in the sump from checking, filling in the field. Not wiping off the cap before removal, or grass/bugs blowing in the opening. Look at pictures of filters from first service magnets, or rear remote quick connects, before forming a empirical opinion on this application. After the first service, hydraulic fluids only real detriment is heat, and water emulsion. Tractors use a suction filter, unlike say an engine. Trash is captured before reaching the pump or any close tolerance part. The HST has its own feed fine particle filter separate from the sump. The only trash a hst will see is from a filter change, engine hyd pump failure, or it grenade itself. The machine is literally built to deal with trash.