not all batiks are created equal...and many do bleed! it just depends. and there are certain colors that tend to almost always bleed...like reds/ purples...
synthropol in the wash will keep dyes from getting on other fabrics; vinegar really only sets (acid dyes)
hand dyes should always be washed separately from anything else...they often run...sometimes bad....i think sometimes people who are doing hand dying are not taking the extra steps of washing the fabrics with synthropol and heat setting them. i dye fabrics myself often and do not have a problem with bleeding when i use them...they get washed 3 or 4 times before i consider them 'done' and if i have one that wants to keep running i separate it to make sure it is not used in anything that will be washed...learned my lesson when i dyed my teenage son's gray socks bubble gum pink...he was not amused ( and i wasn't happy about having to go buy new socks)
when ever you purchase hand dyes...run water through them or put them in a bowl of hot water and swish them around to see if you have a problem fabric...if you do make sure to not put it in with anything that would not (match) use sythropol to keep the color from going anywhere except down the drain and keep washing them until there is no more color in the water.