Inspired by discussion in the comments on this question.
Successfully hiding is normally the result of a 'contest' sometimes known as an 'opposed check'. The person attempting to hide makes a Dexterity (Stealth) roll contested by the Wisdom (Perception) of the person who may or may not be able to see them.
In the case of a tie between these two rolls:
the situation remains the same as it was before the contest. Thus, one contestant might win the contest by default.
How should this ruling be applied with regards to hiding? If, in the event of a tie, 'the situation remains the same as it was before the contest' does that always means the hider has failed to hide? Or can it sometimes mean the hider stays hidden?
Consider the following scenarios (assume hiding is possible and allowed by DM in each and that hider has rolled 15 on stealth):
Hider is chased through a fairly dense forest, gets a little distance between them and their pursuer and attempts to hide. The chaser quickly approaches their hiding place, with a perception check of 15, tieing their stealth roll - result: they failed to hide successfully and are spotted.
Hider is chased through a forest by multiple pursuers, one pretty observant but unfit, one moderately fit but a bit of a daydreamer. The hider, as in scenario 1, gains a little distance on their pursuer and attempts to hide. First on the scene is the Daydreamer, with a perception check of only 12 they blunder straight on, past the hider, deeper into the undergrowth - the hider has successfully hidden from them. Seconds later, the more Observant, but less fit, pursuer comes panting and puffing into view and with their perception check of 15 they tie the hider's stealth roll. What happens next?
a. Does the hider remain hidden? We've already had an opposed check which has concluded that they have successfully hidden. So, if we resolve the tie by the situation 'remaining the same' then does that mean the hider remains hidden? That would mean that the pursuer's chances of finding their quarry had been actively harmed, rather than helped by their companion. Their chance of finding him is now 5% worse.
b. Or, is the hider discovered? Can we argue that the first contested check is entirely unrelated to the second? The first situation has resolved that the hider is hidden with respect to the Daydreamer. But in the second check the hider (with the same stealth roll) is attempting to hide from someone different. With respect to the observant pursuer they have failed to successfully hide and so are spotted.
Finally, is the result of any of the above scenarios changed if the amount of time that elapses between actions (hiding v. percieving) is lengthened?